diff --git a/src/core/event/sidebar.js b/src/core/event/sidebar.js
index b15cb2afe..7ca72d94c 100644
--- a/src/core/event/sidebar.js
+++ b/src/core/event/sidebar.js
@@ -86,6 +86,8 @@ export function getAndActive(router, el, isParent, autoTitle) {
       const href = a.getAttribute('href');
       const node = isParent ? a.parentNode : a;
 
+      a.title = a.innerText;
+
       if (hash.indexOf(href) === 0 && !target) {
         target = a;
         dom.toggleClass(node, 'add', 'active');
diff --git a/src/core/render/tpl.js b/src/core/render/tpl.js
index e3b35a5c3..2bad3a311 100644
--- a/src/core/render/tpl.js
+++ b/src/core/render/tpl.js
@@ -91,7 +91,7 @@ export function tree(toc, tpl = '<ul class="app-sub-sidebar">{inner}</ul>') {
 
   let innerHTML = '';
   toc.forEach(node => {
-    innerHTML += `<li><a class="section-link" href="${node.slug}">${node.title}</a></li>`;
+    innerHTML += `<li><a class="section-link" href="${node.slug}" title="${node.title}">${node.title}</a></li>`;
     if (node.children) {
       innerHTML += tree(node.children, tpl);
     }