diff --git a/code/app/model/GanRaoMaModel.php b/code/app/model/GanRaoMaModel.php
index 18720ae..bcaf674 100644
--- a/code/app/model/GanRaoMaModel.php
+++ b/code/app/model/GanRaoMaModel.php
@@ -196,23 +196,22 @@ class GanRaoMaModel extends MongoModel
     }
 
 
-
     /**
      * Undocumented function
      *
      * @param string $strDomain  域名
      * @param string $strPageCode  视图编码
-     * @param string $strDifference  差异
-     * @param int  $intNum         生成数量
+     * @param string|NULL $strDifference  差异
+     * @param integer $intNum 生成数量
      * @return array
      */
-    static public function getGrmCode($strDomain, $strPageCode,  $strDifference, $intNum)
+    static public function getGrmCode(string $strDomain, string $strPageCode, string|NULL $strDifference, int $intNum)
     {
 
         $arrFilter = [
             'grm_domain' => (string) $strDomain,
             'grm_page_code' => (string) $strPageCode,
-            'grm_page_diff' => (string) $strDifference,
+            'grm_page_diff' => (string) $strDifference ?? '0',
         ];
         $arrResult =  self::getInstance()->getOne($arrFilter, self::$arrOptions);
 
diff --git a/code/app/services/SiteContext.php b/code/app/services/SiteContext.php
index ed936b4..be8a23f 100644
--- a/code/app/services/SiteContext.php
+++ b/code/app/services/SiteContext.php
@@ -209,11 +209,11 @@ class SiteContext
      * 获取干扰码
      *
      * @param string $strPageCode
-     * @param string $strDiff
+     * @param string|NULL $strDiff
      * @param integer $intNum
      * @return array
      */
-    public function generateGrm(string $strPageCode, string $strDiff, int $intNum): array
+    public function generateGrm(string $strPageCode, string|NULL $strDiff, int $intNum): array
     {
         $strDomain = $this->DomainModel->d_domain;