diff --git a/web/admin/md_check.php b/web/admin/md_check.php
new file mode 100644
index 0000000..df23da0
--- /dev/null
+++ b/web/admin/md_check.php
@@ -0,0 +1,17 @@
+<?php
+function decodeMarkdownEntities($markdown) {
+    // Decode HTML entities in code blocks
+    $markdown = preg_replace_callback('/(```.*?```|`[^`]*`)/s', function ($matches) {
+        return htmlentities($matches[0], ENT_QUOTES, 'UTF-8');
+    }, $markdown);
+
+    // Decode HTML entities in inline math and display math
+    $markdown = preg_replace_callback('/(\$\$.*?\$\$|\$[^$]*\$)/s', function ($matches) {
+        return htmlentities($matches[0], ENT_QUOTES, 'UTF-8');
+    }, $markdown);
+    // 特殊转义
+    $markdown = str_replace("<p>", "", $markdown);
+    $markdown = str_replace("</p>", "\n\n", $markdown);
+    $markdown = str_replace("<br />", "\n\n", $markdown);
+    return $markdown;
+}
diff --git a/web/admin/problem_add.php b/web/admin/problem_add.php
index ca9af06..cb9a85e 100644
--- a/web/admin/problem_add.php
+++ b/web/admin/problem_add.php
@@ -1,5 +1,6 @@
 <?php
 require_once ("admin-header.php");
+require_once ("md_check.php");
 require_once("../include/check_post_key.php");
 if (!(isset($_SESSION[$OJ_NAME.'_'.'administrator']) || isset($_SESSION[$OJ_NAME.'_'.'contest_creator']) || isset($_SESSION[$OJ_NAME.'_'.'problem_editor']))) {
   echo "<a href='../loginpage.php'>Please Login First!</a>";
@@ -12,45 +13,26 @@ require_once ("../include/problem.php");
 
 // contest_id
 $title = $_POST['title'];
-// $title = str_replace(",", "&#44;", $title);
-// $title = html_entity_decode($title, ENT_QUOTES, 'UTF-8');
 
 $time_limit = $_POST['time_limit'];
 $memory_limit = $_POST['memory_limit'];
 
 $description = $_POST['description'];
-//$description = str_replace("<p>", "", $description); 
-//$description = str_replace("</p>", "<br />", $description);
-// $description = str_replace(",", "&#44;", $description); 
-// $description = html_entity_decode($description, ENT_QUOTES, 'UTF-8');
+$description = decodeMarkdownEntities($description);
 
 $input = $_POST['input'];
-//$input = str_replace("<p>", "", $input); 
-//$input = str_replace("</p>", "<br />", $input); 
-// $input = str_replace(",", "&#44;", $input);
-// $input = html_entity_decode($input, ENT_QUOTES, 'UTF-8');
+$input = decodeMarkdownEntities($input);
 
 $output = $_POST['output'];
-//$output = str_replace("<p>", "", $output); 
-//$output = str_replace("</p>", "<br />", $output);
-// $output = str_replace(",", "&#44;", $output);
-// $output = html_entity_decode($output, ENT_QUOTES, 'UTF-8');
+$output = decodeMarkdownEntities($output);
 
 $sample_input = $_POST['sample_input'];
 $sample_output = $_POST['sample_output'];
 $test_input = $_POST['test_input'];
 $test_output = $_POST['test_output'];
-/* don't do this , we will left them empty for not generating invalid test data files 
-if ($sample_input=="") $sample_input="\n";
-if ($sample_output=="") $sample_output="\n";
-if ($test_input=="") $test_input="\n";
-if ($test_output=="") $test_output="\n";
-*/
+
 $hint = $_POST['hint'];
-//$hint = str_replace("<p>", "", $hint); 
-//$hint = str_replace("</p>", "<br />", $hint); 
-// $hint = str_replace(",", "&#44;", $hint);
-// $hint = html_entity_decode($hint, ENT_QUOTES, 'UTF-8');
+$hint = decodeMarkdownEntities($hint);
 
 $source = $_POST['source'];
 
diff --git a/web/admin/problem_edit.php b/web/admin/problem_edit.php
index 5b0a1a5..78f6e2e 100644
--- a/web/admin/problem_edit.php
+++ b/web/admin/problem_edit.php
@@ -1,6 +1,7 @@
 <?php
 require_once("../include/db_info.inc.php");
 require_once("admin-header.php");
+require_once ("md_check.php");
 require_once("../include/my_func.inc.php");
 
 if (!(isset($_SESSION[$OJ_NAME.'_'.'administrator']) || isset($_SESSION[$OJ_NAME.'_'.'problem_editor']))) {
@@ -227,29 +228,20 @@ include_once("kindeditor.php") ;
       if (!(isset($_SESSION[$OJ_NAME.'_'."p$id"]) || isset($_SESSION[$OJ_NAME.'_'.'administrator']) || isset($_SESSION[$OJ_NAME.'_'.'problem_editor']) )) exit();
 
       $title = $_POST['title'];
-      // $title = html_entity_decode($title,ENT_QUOTES,"UTF-8");
 
       $time_limit = $_POST['time_limit'];
 
       $memory_limit = $_POST['memory_limit'];
 
       $description = $_POST['description'];
-     // $description = str_replace("<p>", "", $description);
-     // $description = str_replace("</p>", "<br />", $description);
-      // $description = str_replace(",", "&#44;", $description);
-      // $description = html_entity_decode($description,ENT_QUOTES,"UTF-8");
+      $description = decodeMarkdownEntities($description);
 
       $input = $_POST['input'];
-     // $input = str_replace("<p>", "", $input);
-     // $input = str_replace("</p>", "<br />", $input);
-      // $input = str_replace(",", "&#44;", $input);
-      // $input = html_entity_decode($input,ENT_QUOTES,"UTF-8");
+      $input = decodeMarkdownEntities($input);
+      
 
       $output = $_POST['output'];
-     // $output = str_replace("<p>", "", $output);
-     // $output = str_replace("</p>", "<br />", $output);
-      // $output = str_replace(",", "&#44;", $output);
-      // $output = html_entity_decode($output,ENT_QUOTES,"UTF-8");
+      $output = decodeMarkdownEntities($output);
 
       $sample_input = $_POST['sample_input'];
       $sample_output = $_POST['sample_output'];
@@ -257,10 +249,7 @@ include_once("kindeditor.php") ;
       //if ($sample_output=="") $sample_output="\n";
 
       $hint = $_POST['hint'];
-     // $hint = str_replace("<p>", "", $hint);
-    //  $hint = str_replace("</p>", "<br />", $hint);
-      // $hint = str_replace(",", "&#44;", $hint);
-      // $hint = html_entity_decode($hint,ENT_QUOTES,"UTF-8");
+      $hint = decodeMarkdownEntities($hint);
 
       $source = $_POST['source'];
       $remote_oj= $_POST['remote_oj'];