diff --git a/application/common.php b/application/common.php
index 68b9e582..f12cae60 100755
--- a/application/common.php
+++ b/application/common.php
@@ -87,6 +87,7 @@ if (!function_exists('cdnurl')) {
      */
     function cdnurl($url, $domain = false)
     {
+        if(!$url) return '';
         $regex = "/^((?:[a-z]+:)?\/\/|data:image\/)(.*)/i";
         if (is_bool($domain)) {
             $cdnurl = \think\Config::get('upload.cdnurl');