diff --git a/app/admin/controller/Post.php b/app/admin/controller/Post.php
index b154638..e697905 100644
--- a/app/admin/controller/Post.php
+++ b/app/admin/controller/Post.php
@@ -9,6 +9,7 @@ use app\model\Post as ModelPost;
 use app\model\PostCategory;
 use app\model\PostTag;
 use app\model\Tag;
+use think\facade\Cache;
 use think\facade\Route;
 use think\facade\View;
 use think\Request;
@@ -201,8 +202,7 @@ class Post extends Common
 
         $model_post->save($post_data);
 
-
-
+        Cache::delete('sitemap_last_etag');
 
         return $this->success('保存成功', url('index', ['type' => $model_post->getData('type')]));
     }
diff --git a/route/app.php b/route/app.php
index 4797fab..5a2f059 100644
--- a/route/app.php
+++ b/route/app.php
@@ -10,10 +10,34 @@
 // +----------------------------------------------------------------------
 
 use app\common\tools\Sitemap;
+use app\Request;
+use think\facade\Cache;
+use think\facade\Log;
 use think\facade\Route;
 
-Route::rule('/site.xml', function () {
+Route::rule('/site.xml', function (Request $request) {
+
+    $cache_key = 'sitemap_last_etag';
+
+    $last_etag = Cache::get($cache_key);
+
+    if (!empty($cache_key)) {
+
+        $if_not_match = $request->header('If-None-Match');
+
+        if (!empty($if_not_match)) {
+            if ($if_not_match == $last_etag) {
+                Log::debug('sitemap go for etag cache');
+                return xml('', 304)->eTag($last_etag);
+            }
+        }
+    }
+
     $content = Sitemap::init();
 
-    return xml($content);
+    $last_etag = md5($content);
+
+    Cache::set($cache_key, $last_etag);
+
+    return xml($content)->eTag($last_etag);
 });