diff --git a/modules/api.js b/modules/api.js
index 8731053..0ece71e 100644
--- a/modules/api.js
+++ b/modules/api.js
@@ -72,6 +72,14 @@ app.post('/api/sign_up', async (req, res) => {
     user = await User.findOne({ where: { email: req.body.email } });
     if (user) throw 2009;
 
+    if (!req.body.nickname) {
+      res.send({
+        error_code: 2300,
+        message : "昵称不能为空"
+      });
+      return;
+    }
+
 
     // Because the salt is "syzoj2_xxx" and the "syzoj2_xxx" 's md5 is"59cb..."
     // the empty password 's md5 will equal "59cb.."
@@ -79,6 +87,13 @@ app.post('/api/sign_up', async (req, res) => {
     if (req.body.password === syzoj2_xxx_md5) throw 2007;
     if (!(req.body.email = req.body.email.trim())) throw 2006;
     if (!syzoj.utils.isValidUsername(req.body.username)) throw 2002;
+    if (!syzoj.utils.isValidEmail(req.body.email)) {
+       res.send({
+         error_code: 2300,
+         message : "邮箱需要以" + syzoj.config.email_suffix + "结尾"
+       });
+       return;
+    }
 
     if (syzoj.config.register_mail) {
       let sendObj = {
@@ -110,6 +125,7 @@ app.post('/api/sign_up', async (req, res) => {
       user = await User.create({
         username: req.body.username,
         password: req.body.password,
+        nickname:req.body.nickname,
         email: req.body.email,
         is_show: syzoj.config.default.user.show,
         rating: syzoj.config.default.user.rating,
diff --git a/modules/user.js b/modules/user.js
index ab559ab..180ec83 100644
--- a/modules/user.js
+++ b/modules/user.js
@@ -175,6 +175,8 @@ app.post('/user/:id/edit', async (req, res) => {
       user.username = req.body.username;
       user.email = req.body.email;
     }
+    if (!req.body.nickname) throw new ErrorMessage('昵称不能为空。');
+    user.nickname = req.body.nickname;
 
     if (res.locals.user && res.locals.user.is_admin) {
       if (!req.body.privileges) {
diff --git a/utility.js b/utility.js
index f8a0903..7f36b4f 100644
--- a/utility.js
+++ b/utility.js
@@ -270,6 +270,9 @@ module.exports = {
   isValidUsername(s) {
     return RegExp(syzoj.config.username_regex).test(s);
   },
+  isValidEmail(s) {
+    return s.endsWith(syzoj.config.email_suffix || "");
+  },
   locks: [],
   lock(key, cb) {
     let s = JSON.stringify(key);
diff --git a/views/index.ejs b/views/index.ejs
index 397b9c5..ed1cd91 100644
--- a/views/index.ejs
+++ b/views/index.ejs
@@ -28,7 +28,7 @@
           <thead>
             <tr>
 	            <th style="width: 50px; ">#</th>
-	            <th style="width: 170px; ">用户名</th>
+	            <th style="width: 170px; ">用户</th>
               <th style="width: 170px; ">积分</th>
 	            <th>个性签名</th>
             </tr>
@@ -53,7 +53,7 @@
             %>
                 <tr>
                     <td><b><%= i %></b></td>
-                    <td><a href="<%= syzoj.utils.makeUrl(['user', user.id]) %>"><%= user.username %></a><% if (user.nameplate) { %><%- user.nameplate %><% } %></td>
+                    <td><a href="<%= syzoj.utils.makeUrl(['user', user.id]) %>"><%= user.nickname %></a><% if (user.nameplate) { %><%- user.nameplate %><% } %></td>
                     <td><%= user.rating %></td>
                     <td style="font-content">
                       <script id="user-infomation-script-<%= i %>">
diff --git a/views/ranklist.ejs b/views/ranklist.ejs
index 7e94ce2..46700d0 100644
--- a/views/ranklist.ejs
+++ b/views/ranklist.ejs
@@ -42,7 +42,7 @@
 		        	<td><a href="<%= syzoj.utils.makeUrl(['user', user.id]) %>"><%= user.username %></a><% if (user.nameplate) { %><%- user.nameplate %><% } %></td>
 		        	<td><%= user.ac_num %></td>
               <td><%= user.submit_num %></td>
-              <td><%= user.submit_num == 0 ? 0 : Math.round(user.ac_num / user.submit_num * 10000) / 100.00 + "%" %></td>
+              <td><%= user.ac_num && user.submit_num ? Math.round(user.ac_num / user.submit_num * 10000) / 100.00 + "%" : 0%></td>
 		        	<td><%= user.rating %></td>
 		        </tr>
 		    <% } %>
diff --git a/views/sign_up.ejs b/views/sign_up.ejs
index edb7507..435e83d 100644
--- a/views/sign_up.ejs
+++ b/views/sign_up.ejs
@@ -5,110 +5,118 @@
   <div class="ui error message" id="error" data-am-alert hidden>
     <p id="error_info"></p>
   </div>
-          <form class="ui form">
-                <div class="field">
-                    <label for="username">用户名</label>
-                    <input type="text" placeholder="" id="username">
-                </div>
-                <div class="field">
-                    <label for="email">邮箱</label>
-                    <input type="email" placeholder="" id="email">
-                </div>
-                <div class="two fields">
-                    <div class="field">
-                    <label class="ui header">密码</label>
-                      <input type="password" placeholder="" id="password1">
-                    </div>
-                    <div class="field">
-                      <label class="ui header">确认密码</label>
-                      <input type="password" placeholder="" id="password2">
-                    </div>
-                </div>
-                <a id="sign_up" class="ui button" href="javascript:submit();">注册</a>
-            </form>
+  <form class="ui form">
+    <div class="field">
+      <label for="username">用户名</label>
+      <input type="text" placeholder="" id="username">
+    </div>
+    <div class="field">
+      <label for="nickname">昵称</label>
+      <input type="text" placeholder="" id="nickname">
+    </div>
+    <div class="field">
+      <label for="email">邮箱</label>
+      <input type="email" placeholder="" id="email">
+    </div>
+    <div class="two fields">
+      <div class="field">
+        <label class="ui header">密码</label>
+        <input type="password" placeholder="" id="password1">
+      </div>
+      <div class="field">
+        <label class="ui header">确认密码</label>
+        <input type="password" placeholder="" id="password2">
+      </div>
+    </div>
+    <a id="sign_up" class="ui button" href="javascript:submit();">注册</a>
+  </form>
 </div>
 <script src="<%- lib('blueimp-md5/2.10.0/js/md5.min.js') %>"></script>
 <script type="text/javascript">
-function show_error(error) {
+  function show_error(error) {
     $("#error_info").text(error);
     $("#error").show();
-}
+  }
 
-function success() {
+  function success() {
     alert("注册成功！");
     window.location.href = location.protocol + '//' + location.host + <%- serializejs(req.query.url || '/') %>;
-}
+  }
 
-function mail_required() {
+  function mail_required() {
     alert("注册确认邮件已经发送到您的邮箱的垃圾箱，点击邮件内的链接即可完成注册。");
     var s = $("#email").val();
     var mailWebsite = 'https://mail.' + s.substring(s.indexOf('@') + 1, s.length);
     if (mailWebsite === 'https://mail.gmail.com') mailWebsite = 'https://mail.google.com';
     window.location.href = mailWebsite;
-}
+  }
 
-function submit() {
+  function submit() {
     if ($("#password1").val() != $("#password2").val()) {
-        show_error("两次输入的密码不一致");
-        return;
+      show_error("两次输入的密码不一致");
+      return;
     }
     password = md5($("#password1").val() + "syzoj2_xxx")
     $("#sign_up").addClass("loading");
     $.ajax({
-        url: '/api/sign_up',
-        type: 'POST',
-        async: true,
-        data: {
-          username: $("#username").val(),
-          password: password,
-          email: $("#email").val(),
-          prevUrl: <%- serializejs(req.query.url || '/') %>
-        },
-        success: function(data) {
-            error_code = data.error_code;
-            switch(error_code){
-                case 2001:
-                    show_error("服务器未收到数据");
-                    break;
-                case 2005:
-                case 2002:
-                    show_error("用户名需要大于 3 个字符小于 16 个字符，仅允许字母数字和下划线");
-                    break;
-                case 2007:
-                case 2003:
-                    show_error("密码不得为空");
-                    break;
-                case 2004:
-                case 2006:
-                    show_error("请输入正确的邮箱");
-                    break;
-                case 2008:
-                    show_error("已经有人用过这个用户名了");
-                    break;
-                case 2009:
-                    show_error("邮箱地址已被占用");
-                    break;
-                case 2010:
-                    show_error("验证邮件发送失败：\n" + data.message);
-                    break;
-                case 1:
-                    success();
-                    break;
-                case 2:
-                    mail_required();
-                    break;
-                default:
-                    show_error("未知错误：" + JSON.stringify(data));
-                    break;
-            }
-            $("#sign_up").removeClass("loading");
-        },
-        error: function(XMLHttpRequest, textStatus, errorThrown) {
-            alert(XMLHttpRequest.responseText);
-            show_error("未知错误");
-            $("#sign_up").removeClass("loading");
+      url: '/api/sign_up',
+      type: 'POST',
+      async: true,
+      data: {
+        username: $("#username").val(),
+        nickname: $("#nickname").val(),
+        password: password,
+        email: $("#email").val(),
+        prevUrl: <%- serializejs(req.query.url || '/') %>
+      },
+      success: function (data) {
+        error_code = data.error_code;
+        switch (error_code) {
+          case 2001:
+            show_error("服务器未收到数据");
+            break;
+          case 2005:
+          case 2002:
+            show_error("用户名仅允许字母数字和下划线和点");
+            break;
+          case 2007:
+          case 2003:
+            show_error("密码不得为空");
+            break;
+          case 2004:
+          case 2006:
+            show_error("请输入正确的邮箱");
+            break;
+          case 2008:
+            show_error("已经有人用过这个用户名了");
+            break;
+          case 2009:
+            show_error("邮箱地址已被占用");
+            break;
+          case 2010:
+            show_error("验证邮件发送失败：\n" + data.message);
+            break;
+          case 2300:
+            show_error(data.message);
+            break;
+          case 1:
+            success();
+            break;
+          case 2:
+            mail_required();
+            break;
+          default:
+            show_error("未知错误：" + JSON.stringify(data));
+            break;
         }
+        $("#sign_up").removeClass("loading");
+      },
+      error: function (XMLHttpRequest, textStatus, errorThrown) {
+        alert(XMLHttpRequest.responseText);
+        show_error("未知错误");
+        $("#sign_up").removeClass("loading");
+      }
     });
-}
+  }
 </script>
 <% include footer %>
diff --git a/views/user.ejs b/views/user.ejs
index f7c9d73..f6c63b9 100644
--- a/views/user.ejs
+++ b/views/user.ejs
@@ -50,6 +50,12 @@
                                            <div class="ui bottom attached segment"><%= show_user.username %><% if (show_user.nameplate) { %><%- show_user.nameplate %><% } %></div>
                                         </div>
                                     </div>
+                                  <div class="row">
+                                    <div class="column">
+                                      <h4 class="ui top attached block header">昵称</h4>
+                                      <div class="ui bottom attached segment"><%= show_user.nickname %></div>
+                                    </div>
+                                  </div>
                                     <% if (show_user.emailVisible) { %>
                                       <div class="row">
                                           <div class="column">
diff --git a/views/user_edit.ejs b/views/user_edit.ejs
index 583dad0..54e360e 100644
--- a/views/user_edit.ejs
+++ b/views/user_edit.ejs
@@ -2,58 +2,79 @@
 <% include header %>
 <% include monaco-editor %>
 <div class="padding">
-    <div class="ui <% if (error_info === '') { %>success<% } else { %>error<% } %> message" id="error" <% if (error_info === null) { %>hidden<% } %>>
-      <% if (error_info !== null) {
-          if (error_info === '') error_info = '修改成功。';
-      %>
-      	<p id="error_info"><%= error_info %></p>
-      <% } %>
-    </div>
-		<form id="form" action="<%= syzoj.utils.makeUrl(['user', edited_user.id, 'edit']) %>" method="post" onsubmit="return check()">
-      <div class="ui form">
+  <div class="ui <% if (error_info === '') { %>success<% } else { %>error<% } %> message" id="error"
+       <% if (error_info === null) { %>hidden
+    <% } %>
+  >
+    <% if (error_info !== null) {
+      if (error_info === '') error_info = '修改成功。';
+    %>
+    <p id="error_info"><%= error_info %></p>
+    <% } %>
+  </div>
+  <form id="form" action="<%= syzoj.utils.makeUrl(['user', edited_user.id, 'edit']) %>" method="post"
+        onsubmit="return check()">
+    <div class="ui form">
       <div class="field">
-	    	<label for="username">用户名</label>
-	    	<input type="text" id="username" name="username" value="<%= edited_user.username %>"<% if (!user.allowedManage) { %> readonly<% } %>>
-	    </div>
+        <label for="username">用户名</label>
+        <input type="text" id="username" name="username" value="<%= edited_user.username %>"
+        <% if (!user.allowedManage) { %> readonly
+          <% } %>
+        >
+      </div>
       <div class="field">
-	    	<label for="sex">性别</label>
-	    	<select class="ui dropdown" name="sex">
-          <option value="0" <%= edited_user.sex == 0 ? 'selected': '' %>>其它</option>
-          <option value="1" <%= edited_user.sex == 1 ? 'selected': '' %>>男</option>
-          <option value="-1" <%= edited_user.sex == -1 ? 'selected': '' %>>女</option>
+        <label for="sex">性别</label>
+        <select class="ui dropdown" name="sex">
+          <option value="0" <%= edited_user.sex == 0 ? 'selected' : '' %>>其它</option>
+          <option value="1" <%= edited_user.sex == 1 ? 'selected' : '' %>>男</option>
+          <option value="-1" <%= edited_user.sex == -1 ? 'selected' : '' %>>女</option>
         </select>
-	    </div>
-	    <div class="field">
-	    	<label for="email">Email</label>
-	    	<input class="font-content" type="email" id="email" name="email" value="<%= edited_user.email %>"<% if (!user.allowedManage) { %> readonly<% } %>>
-	    </div>
+      </div>
+      <div class="field">
+        <label for="email">Email</label>
+        <input class="font-content" type="email" id="email" name="email" value="<%= edited_user.email %>"
+        <% if (!user.allowedManage) { %> readonly
+          <% } %>
+        >
+      </div>
       <div class="inline field">
         <label class="ui header">公开 Email</label>
         <div class="ui toggle checkbox">
-          <input id="public_email" name="public_email" type="checkbox" <% if (edited_user.public_email) { %> checked<% } %>>
+          <input id="public_email" name="public_email" type="checkbox"
+          <% if (edited_user.public_email) { %> checked
+            <% } %>
+          >
           <label>　</label>
         </div>
-	    </div>
+      </div>
       <div class="inline field">
         <label class="ui header">默认显示格式化后的代码（如果可用）</label>
         <div class="ui toggle checkbox">
-          <input id="prefer_formatted_code" name="prefer_formatted_code" type="checkbox" <% if (edited_user.prefer_formatted_code) { %> checked<% } %>>
+          <input id="prefer_formatted_code" name="prefer_formatted_code" type="checkbox"
+          <% if (edited_user.prefer_formatted_code) { %> checked
+            <% } %>
+          >
           <label>　</label>
         </div>
-	    </div>
-	    <div class="field">
+      </div>
+      <div class="field">
         <label for="information">个性签名</label>
       </div>
 
+    </div>
+    <div class="editor editor-with-border" id="information" style="width: 100%; height: 100px; margin-bottom: 1em; ">
+      <%- this.showLoadingEditor(); %>
+    </div>
+    <input type="hidden" name="information">
+    <div class="ui form">
+
+      <div class="field">
+        <label class="ui header">昵称</label>
+        <input type="text" placeholder="昵称" name="nickname" value="<%= edited_user.nickname %>" id="nickname">
       </div>
-      <div class="editor editor-with-border" id="information" style="width: 100%; height: 100px; margin-bottom: 1em; ">
-        <%- this.showLoadingEditor(); %>
-      </div>
-      <input type="hidden" name="information">
-      <div class="ui form">
 
       <div class="field">
-      <label class="ui header">密码</label>
+        <label class="ui header">密码</label>
         <input type="password" placeholder="原密码（留空则不修改）" name="old_password" id="old_password">
       </div>
       <div class="two fields" id="new_password_field">
@@ -70,95 +91,114 @@
       <div class="inline field">
         <label class="ui header">权限</label>
         <div class="ui toggle disabled checkbox" style="margin-right: 20px; ">
-          <input disabled="disabled" type="checkbox" <% if (edited_user.is_admin) { %> checked<% } %>>
+          <input disabled="disabled" type="checkbox"
+          <% if (edited_user.is_admin) { %> checked
+            <% } %>
+          >
           <label>全站管理员</label>
         </div>
-        <div class="ui toggle <% if (!allowedManagePrivilege) { %>disabled <% } %>checkbox checkbox_privilege" data-name="manage_problem" style="margin-right: 20px; ">
-          <input <% if (!allowedManagePrivilege) { %>disabled="disabled" <% } %>type="checkbox"<% if (edited_user.privileges.includes('manage_problem')) { %> checked<% } %>>
+        <div class="ui toggle <% if (!allowedManagePrivilege) { %>disabled <% } %>checkbox checkbox_privilege"
+             data-name="manage_problem" style="margin-right: 20px; ">
+          <input <% if (!allowedManagePrivilege) { %>disabled="disabled" <% } %>type="checkbox"
+          <% if (edited_user.privileges.includes('manage_problem')) { %> checked
+            <% } %>
+          >
           <label>管理题目</label>
         </div>
-        <div class="ui toggle <% if (!allowedManagePrivilege) { %>disabled <% } %>checkbox checkbox_privilege" data-name="manage_problem_tag" style="margin-right: 20px; ">
-          <input <% if (!allowedManagePrivilege) { %>disabled="disabled" <% } %>type="checkbox"<% if (edited_user.privileges.includes('manage_problem_tag')) { %> checked<% } %>>
+        <div class="ui toggle <% if (!allowedManagePrivilege) { %>disabled <% } %>checkbox checkbox_privilege"
+             data-name="manage_problem_tag" style="margin-right: 20px; ">
+          <input <% if (!allowedManagePrivilege) { %>disabled="disabled" <% } %>type="checkbox"
+          <% if (edited_user.privileges.includes('manage_problem_tag')) { %> checked
+            <% } %>
+          >
           <label>管理题目标签</label>
         </div>
-        <div class="ui toggle <% if (!allowedManagePrivilege) { %>disabled <% } %>checkbox checkbox_privilege" data-name="manage_user">
-          <input <% if (!allowedManagePrivilege) { %>disabled="disabled" <% } %>type="checkbox"<% if (edited_user.privileges.includes('manage_user')) { %> checked<% } %>>
+        <div class="ui toggle <% if (!allowedManagePrivilege) { %>disabled <% } %>checkbox checkbox_privilege"
+             data-name="manage_user">
+          <input <% if (!allowedManagePrivilege) { %>disabled="disabled" <% } %>type="checkbox"
+          <% if (edited_user.privileges.includes('manage_user')) { %> checked
+            <% } %>
+          >
           <label>管理用户</label>
         </div>
       </div>
       <div style="text-align: center; margin-top: 30px; ">
-        <button id="submit_button" type="submit" class="ui disabled blue labeled icon button"><i class="ui icon edit"></i>修改</button>
-        <a href="<%= syzoj.utils.makeUrl(['user', edited_user.id]) %>" class="ui labeled icon button"><i class="ui icon angle left"></i>返回</a>
+        <button id="submit_button" type="submit" class="ui disabled blue labeled icon button"><i
+            class="ui icon edit"></i>修改
+        </button>
+        <a href="<%= syzoj.utils.makeUrl(['user', edited_user.id]) %>" class="ui labeled icon button"><i
+            class="ui icon angle left"></i>返回</a>
       </div>
-      </div>
-		</form>
-	</div>
+    </div>
+  </form>
+</div>
 </div>
 <script>
-var bakDefine = define;
-define = undefined;
+  var bakDefine = define;
+  define = undefined;
 </script>
 <script src="<%- lib('blueimp-md5/2.10.0/js/md5.min.js') %>"></script>
 <script>
-define = bakDefine;
+  define = bakDefine;
 </script>
 <script type="text/javascript">
-var editors = {
-  information: { defaultValue: <%- serializejs(edited_user.information) %> },
-};
+  var editors = {
+    information: {defaultValue: <%- serializejs(edited_user.information) %> },
+  };
 
-window.onEditorLoaded(function () {
-  for (var name in editors) {
-    var editor = editors[name];
-    var editorElement = document.getElementById(name);
-    var input = document.getElementsByName(name)[0];
-    editor.editor = window.createMarkdownEditor(editorElement, editor.defaultValue, input);
-  }
-
-  $('#submit_button').removeClass('disabled');
-});
+  window.onEditorLoaded(function () {
+    for (var name in editors) {
+      var editor = editors[name];
+      var editorElement = document.getElementById(name);
+      var input = document.getElementsByName(name)[0];
+      editor.editor = window.createMarkdownEditor(editorElement, editor.defaultValue, input);
+    }
 
-function make_md5(tag) {
-	if (tag.val()) {
-		tag.val(md5(tag.val() + "syzoj2_xxx"));
-	}
-}
-function check() {
-	old_password = $("#old_password");
-	password1 = $("#password1");
-	password2 = $("#password2");
-	if ($("#old_password").val() && password1.val() != password2.val()) {
-		$("#error").removeClass("success");
-		$("#error").removeClass("error");
-		$("#error").addClass("error");
-		$("#error_info").html("两次输入的密码不一致。");
-		$("#error").show();
-		return false;
-	}
-	make_md5(old_password);
-	make_md5(password1);
-	make_md5(password2);
+    $('#submit_button').removeClass('disabled');
+  });
 
-<% if (allowedManagePrivilege) { %>
-  $('.checkbox_privilege').each(function () {
-    if ($(this).checkbox('is checked')) {
-      var name = $(this).data('name');
+  function make_md5(tag) {
+    if (tag.val()) {
+      tag.val(md5(tag.val() + "syzoj2_xxx"));
+    }
+  }
 
-      var elem = document.createElement('input');
-      elem.type = 'hidden';
-      elem.value = name;
-      elem.name = 'privileges';
-      document.getElementById('form').appendChild(elem);
+  function check() {
+    old_password = $("#old_password");
+    password1 = $("#password1");
+    password2 = $("#password2");
+    if ($("#old_password").val() && password1.val() != password2.val()) {
+      $("#error").removeClass("success");
+      $("#error").removeClass("error");
+      $("#error").addClass("error");
+      $("#error_info").html("两次输入的密码不一致。");
+      $("#error").show();
+      return false;
     }
-  });
-<% } %>
+    make_md5(old_password);
+    make_md5(password1);
+    make_md5(password2);
+
+    <% if (allowedManagePrivilege) { %>
+    $('.checkbox_privilege').each(function () {
+      if ($(this).checkbox('is checked')) {
+        var name = $(this).data('name');
 
-	return true;
-}
+        var elem = document.createElement('input');
+        elem.type = 'hidden';
+        elem.value = name;
+        elem.name = 'privileges';
+        document.getElementById('form').appendChild(elem);
+      }
+    });
+    <% } %>
+
+    return true;
+  }
 </script>
 <script>
-$(function () {
-	$('.ui.dropdown:not(.simple)').dropdown();
-});
+  $(function () {
+    $('.ui.dropdown:not(.simple)').dropdown();
+  });
 </script>
 <% include footer %>