diff --git a/webapp/controller/ShopController.class.php b/webapp/controller/ShopController.class.php
index dce731d4..eea3483a 100644
--- a/webapp/controller/ShopController.class.php
+++ b/webapp/controller/ShopController.class.php
@@ -91,7 +91,7 @@ class ShopController extends BaseAuthedController {
         $errCode = 0;
         $errMsg = '';
         if ($itemMeta['type'] == mt\Item::HERO_SKIN_TYPE) {
-            if (!$this->canBuy($itemMeta, $errCode, $errMsg)) {
+            if (!ShopService::canBuy($itemMeta, $errCode, $errMsg)) {
                 myself()->_rspErr($errCode, $errMsg);
                 return;
             }
diff --git a/webapp/services/ShopService.php b/webapp/services/ShopService.php
index 1057383c..c5b4518b 100644
--- a/webapp/services/ShopService.php
+++ b/webapp/services/ShopService.php
@@ -142,7 +142,7 @@ class ShopService {
         );
     }
 
-    private static function canBuy($itemMeta, &$errCode, &$errMsg)
+    public static function canBuy($itemMeta, &$errCode, &$errMsg)
     {
         $errCode = 0;
         $errMsg = '';