diff --git a/src/case/tree/treeexpander/tree.expander.popup.js b/src/case/tree/treeexpander/tree.expander.popup.js
index bf2c6addb..96f9fe259 100644
--- a/src/case/tree/treeexpander/tree.expander.popup.js
+++ b/src/case/tree/treeexpander/tree.expander.popup.js
@@ -22,8 +22,8 @@
             this.popupView.on(BI.Controller.EVENT_CHANGE, function () {
                 self.fireEvent(BI.Controller.EVENT_CHANGE, arguments);
             });
-            this.popupView.element.css("margin-left", -offset * o.layer);
-            this.element.css("margin-left", offset * o.layer);
+            this.popupView.element.css("margin-left", -offset * (o.layer + 1));
+            this.element.css("margin-left", offset * (o.layer + 1));
 
             return {
                 type: "bi.vertical",
diff --git a/src/less/base/tree/tree.expander.less b/src/less/base/tree/tree.expander.less
index 04bdd64ac..b0e6ce76a 100644
--- a/src/less/base/tree/tree.expander.less
+++ b/src/less/base/tree/tree.expander.less
@@ -1,28 +1,42 @@
 @import "../../index.less";
-@import "../../image.less";
 @import "../../lib/icon.less";
-.bi-tree-expander-popup.line:before {
-  position: absolute;
-  content: "";
-  height: 100%;
-  width: 24px;
-  .imagePath(@icon-tree-vertical-line-1, 0, 0, repeat-y);
-}
 
-.bi-tree-expander-popup.line.solid:before {
-  .imagePath(@icon-tree-solid-vertical-line-1, 0, 0, repeat-y);
-  width: 24px;
-  left: 8px;
+.bi-tree-expander-popup.line {
+
+  &:before {
+    border-left: 1px dashed @border-color-dark-gray-line;
+    position: absolute;
+    content: "";
+    height: 100%;
+    left: -1px;
+  }
+
+  &.solid:before {
+    border-left: 1px solid @border-color-dark-gray-line;
+    position: absolute;
+    content: "";
+    height: 100%;
+    left: -1px;
+  }
 }
 
 .bi-theme-dark {
-  .bi-tree-expander-popup.line:before {
-    width: 24px;
-    .imagePath(@icon-tree-vertical-line-1-theme-dark, 0, 0, repeat-y);
-  }
-  .bi-tree-expander-popup.line.solid:before {
-    .imagePath(@icon-tree-solid-vertical-line-1-theme-dark, 0, 0, repeat-y);
-    width: 24px;
-    left: 8px;
+  .bi-tree-expander-popup.line {
+
+    &:before {
+      border-left: 1px dashed @border-color-dark-gray-line-theme-dark;
+      position: absolute;
+      content: "";
+      height: 100%;
+      left: -1px;
+    }
+
+    &.solid:before {
+      border-left: 1px solid @border-color-dark-gray-line-theme-dark;
+      position: absolute;
+      content: "";
+      height: 100%;
+      left: -1px;
+    }
   }
 }