diff --git a/templates/problem/list.html b/templates/problem/list.html
index ca40f89..9baf291 100644
--- a/templates/problem/list.html
+++ b/templates/problem/list.html
@@ -225,7 +225,7 @@
                         </th>
                         <!-- Luong begin -->
                         <th class="pcode">
-                            <a href="">Problem code</a>
+                            <a href="{{ sort_links.code }}">Problem code</a>
                         </th>
                         <!-- Luong end -->
                         <th class="category">