diff --git a/web/problemset.php b/web/problemset.php
index 9e00d0d..0c1e41d 100644
--- a/web/problemset.php
+++ b/web/problemset.php
@@ -41,9 +41,18 @@ $postfix = "";
 $filter_sql = "";
 $limit_sql = "";
 $order_by = " order by problem_id ";
+$filter_params = array();
+$hardness = 0;
+if (isset($_GET['hardness'])) {
+	$hardness = intval($_GET['hardness']);
+	if ($hardness < 1 || $hardness > 8)
+		$hardness = 0;
+}
 if (isset($_GET['search']) && trim($_GET['search']) != "") {
 	$search = "%" . ($_GET['search']) . "%";
 	$filter_sql = " ( title like ? or source like ?)";
+	$filter_params[] = $search;
+	$filter_params[] = $search;
 	$limit_sql = " LIMIT " . ($page - 1) * $page_cnt . "," . $page_cnt;
 	$postfix = "&search=" . urlencode($_GET['search']);
 } else if (isset($_GET['list']) && trim($_GET['list'] != "")) {
@@ -61,6 +70,11 @@ if (isset($_GET['search']) && trim($_GET['search']) != "") {
 	$filter_sql = " 1";
 	$limit_sql = " LIMIT " . ($page - 1) * $page_cnt . "," . $page_cnt;
 }
+if ($hardness > 0) {
+	$filter_sql .= " and hardness=?";
+	$filter_params[] = $hardness;
+	$postfix .= "&hardness=" . $hardness;
+}
 
 //all submit
 //all acc
@@ -103,10 +117,10 @@ pdo_query("SET sort_buffer_size = 1024*1024");   // Out of sort memory, consider
 $sql = "SELECT `problem_id`,`title`,`source`,`submit`,`accepted`,defunct FROM problem A WHERE $filter_sql $order_by $limit_sql ";
 $count_sql = "SELECT count(1) from problem where  $filter_sql ";
 //echo htmlentities( $sql);
-if (isset($_GET['search']) && trim($_GET['search']) != "") {
-	$total = pdo_query($count_sql, $search, $search);
+if (count($filter_params) > 0) {
+	$total = pdo_query($count_sql, ...$filter_params);
 	$cnt = $total[0][0] / $page_cnt;
-	$result = pdo_query($sql, $search, $search);
+	$result = pdo_query($sql, ...$filter_params);
 } else {
 	$total = mysql_query_cache($count_sql);
 	$cnt = $total[0][0] / $page_cnt;
diff --git a/web/template/syzoj/problemset.php b/web/template/syzoj/problemset.php
index d5fadf9..e669e13 100644
--- a/web/template/syzoj/problemset.php
+++ b/web/template/syzoj/problemset.php
@@ -6,41 +6,48 @@
     <div class="row" style="white-space: nowrap; ">
       <div class="seven wide column">
         <form action="" method="get">
-          <div class="ui search" style="width: 160px; height: 28px; margin-top: -5.3px; float:left; margin-right: 10px;">
+          <div class="ui search"
+            style="width: 160px; height: 28px; margin-top: -5.3px; float:left; margin-right: 10px;">
             <div class="ui left icon input" style="width: 100%; ">
               <input class="prompt" style="width: 100%; " type="text" placeholder="<?php echo $MSG_TITLE; ?> …"
                 name="search" value="<?php if (isset($_GET['search']))
                   echo htmlentities($_GET['search'], ENT_QUOTES, 'UTF-8') ?>">
-              <i class="search icon"></i>
+                <i class="search icon"></i>
+              </div>
+              <div class="results" style="width: 100%; "></div>
+            </div>
+
+            <div class="ui selection dropdown" style="width: 120px; height: 28px; margin-top: -5.3px; float:left; margin-right: 10px;">
+              <input type="hidden" name="hardness" value="<?php
+              $selected_hardness = 0;
+              if (isset($_GET['hardness'])) {
+                $selected_hardness = intval($_GET['hardness']);
+                if ($selected_hardness < 1 || $selected_hardness > 8)
+                  $selected_hardness = 0;
+              }
+              echo $selected_hardness;
+              ?>">
+              <i class="dropdown icon"></i>
+              <div class="default text">难度</div>
+              <div class="menu">
+                <div class="item" data-value="0">全部难度</div>
+                <?php for ($h = 1; $h <= 8; $h++) {
+                  echo '<div class="item" data-value="' . $h . '">难度 ' . $h . '</div>';
+                } ?>
+              </div>
             </div>
-            <div class="results" style="width: 100%; "></div>
-          </div>
-          
-          <!-- 添加难度按钮 -->
-          <!-- <div style="display: inline-block; margin-left: 10px; vertical-align: top;">
-            <?php for ($i = 1; $i <= 8; $i++): ?>
-              <button 
-                type="button" 
-                class="ui mini basic button difficulty-btn" 
-                data-difficulty="<?php echo $i; ?>"
-                style="margin-right: 5px; margin-bottom: 5px;"
-              >
-                难度<?php echo $i; ?>
-              </button>
-            <?php endfor; ?>
-          </div> -->
 
           <?php if (isset($_SESSION[$OJ_NAME . '_' . 'administrator'])): ?>
             <div class="ui search" style="width: 120px; height: 28px; margin-top: -5.3px; display: inline-block;">
               <div class="ui icon input" style="width: 100%; ">
                 <input class="prompt" style="width: 100%; " type="text" placeholder="用户ID" name="query_user_id" value="<?php if (isset($_GET['query_user_id']))
                   echo htmlentities($_GET['query_user_id'], ENT_QUOTES, 'UTF-8') ?>">
-                <i class="search icon"></i>
+                  <i class="search icon"></i>
+                </div>
+                <div class="results" style="width: 100%; "></div>
               </div>
-              <div class="results" style="width: 100%; "></div>
-            </div>
           <?php endif; ?>
-          
+
           <button type="submit" class="ui mini button" style="display: none;">搜索</button>
         </form>
       </div>
@@ -97,13 +104,13 @@
                 if (checked) {
                   document.getElementById('show_solved_style').innerHTML = '';
                   // 显示所有题目
-                  document.querySelectorAll('.solved-problem').forEach(function(row) {
+                  document.querySelectorAll('.solved-problem').forEach(function (row) {
                     row.style.display = '';
                   });
                 } else {
                   document.getElementById('show_solved_style').innerHTML = '.solved-problem { display: none; }';
                   // 隐藏已解决的题目
-                  document.querySelectorAll('.solved-problem').forEach(function(row) {
+                  document.querySelectorAll('.solved-problem').forEach(function (row) {
                     row.style.display = 'none';
                   });
                 }
@@ -123,40 +130,15 @@
   </div>
 
   <script>
-    // 添加难度按钮点击事件
-    document.querySelectorAll('.difficulty-btn').forEach(button => {
-      button.addEventListener('click', function() {
-        const difficulty = this.getAttribute('data-difficulty');
-        
-        // 创建隐藏表单提交
-        const form = document.createElement('form');
-        form.method = 'get';
-        form.action = '';
-        
-        // 添加难度参数
-        const input = document.createElement('input');
-        input.type = 'hidden';
-        input.name = 'difficulty';
-        input.value = difficulty;
-        form.appendChild(input);
-        
-        // 保留现有搜索参数
-        const existingSearch = document.querySelector('input[name="search"]');
-        if (existingSearch && existingSearch.value) {
-          const searchInput = document.createElement('input');
-          searchInput.type = 'hidden';
-          searchInput.name = 'search';
-          searchInput.value = existingSearch.value;
-          form.appendChild(searchInput);
+    $(function () {
+      $('.ui.dropdown').dropdown({
+        onChange: function () {
+          $(this).closest('form').submit();
         }
-        
-        // 提交表单
-        document.body.appendChild(form);
-        form.submit();
       });
     });
   </script>
-  
+
   <?php if (!isset($_GET['list'])) { ?>
 
     <div style="margin-bottom: 30px; ">
@@ -319,4 +301,4 @@
     <script type="text/javascript" src="include/jquery.tablesorter.js"></script>
 
   </div>
-  <?php include("template/$OJ_TEMPLATE/footer.php"); ?>
+  <?php include("template/$OJ_TEMPLATE/footer.php"); ?>
\ No newline at end of file