diff --git a/app.js b/app.js
index 46f10df..59e9bea 100644
--- a/app.js
+++ b/app.js
@@ -121,19 +121,48 @@ global.syzoj = {
 
     app.use((req, res, next) => {
       // req.session.user_id = 1;
+      let User = syzoj.model('user');
       if (req.session.user_id) {
-        let User = syzoj.model('user');
         User.fromID(req.session.user_id).then((user) => {
           res.locals.user = user;
           next();
         }).catch((err) => {
           this.log(err);
-          res.locals.user = req.session.user_id = null;
+          res.locals.user = null;
+          req.session.user_id = null;
           next();
         })
       } else {
-        res.locals.user = req.session.user_id = null;
-        next();
+        if (req.cookies.login) {
+          let obj;
+          try {
+            obj = JSON.parse(req.cookies.login);
+            User.findOne({
+              where: {
+                username: obj[0],
+                password: obj[1]
+              }
+            }).then(user => {
+              if (!user) throw null;
+              res.locals.user = user;
+              req.session.user_id = user.id;
+              next();
+            }).catch(err => {
+              console.log(err);
+              res.locals.user = null;
+              req.session.user_id = null;
+              next();
+            });
+          } catch (e) {
+            res.locals.user = null;
+            req.session.user_id = null;
+            next();
+          }
+        } else {
+          res.locals.user = null;
+          req.session.user_id = null;
+          next();
+        }
       }
     });
 
diff --git a/modules/api.js b/modules/api.js
index 140644c..5c660e4 100644
--- a/modules/api.js
+++ b/modules/api.js
@@ -25,6 +25,10 @@ let WaitingJudge = syzoj.model('waiting_judge');
 let JudgeState = syzoj.model('judge_state');
 let TestData = syzoj.model('testdata');
 
+function setLoginCookie(username, password, res) {
+  res.cookie('login', JSON.stringify([username, password]));
+}
+
 // Login
 app.post('/api/login', async (req, res) => {
   try {
@@ -35,6 +39,7 @@ app.post('/api/login', async (req, res) => {
     else if (user.password !== req.body.password) res.send({ error_code: 1002 });
     else {
       req.session.user_id = user.id;
+      setLoginCookie(user.username, user.password, res);
       res.send({ error_code: 1 });
     }
   } catch (e) {
@@ -65,6 +70,8 @@ app.post('/api/sign_up', async (req, res) => {
     await user.save();
 
     req.session.user_id = user.id;
+    setLoginCookie(user.username, user.password, res);
+
     res.send(JSON.stringify({ error_code: 1 }));
   } catch (e) {
     syzoj.log(e);
diff --git a/modules/user.js b/modules/user.js
index de02e65..b80d4ef 100644
--- a/modules/user.js
+++ b/modules/user.js
@@ -78,6 +78,7 @@ app.get('/sign_up', async (req, res) => {
 // Logout
 app.get('/logout', async (req, res) => {
   req.session.user_id = null;
+  res.clearCookie('login');
   res.redirect(req.query.url || '/');
 });