diff --git a/webapp/controller/ShopController.class.php b/webapp/controller/ShopController.class.php
index 79047e3c..280b8b7c 100644
--- a/webapp/controller/ShopController.class.php
+++ b/webapp/controller/ShopController.class.php
@@ -1048,7 +1048,7 @@ class ShopController extends BaseAuthedController
         $count = getReqVal('count', 0);
 
         $conn = $this->_getMysql('');
-        error_log("buyGoodsDS start " + json_encode(array(
+        error_log("buyGoodsDS start " . json_encode(array(
             'idx' => $idx,
             'grid' => $grid,
             'count' => $count,
@@ -1067,7 +1067,7 @@ class ShopController extends BaseAuthedController
             array('idx' => $idx)
         );
 
-        error_log("buyGoodsDS start " + json_encode(array(
+        error_log("buyGoodsDS start " . json_encode(array(
             'idx' => $idx,
             'grid' => $grid,
             'count' => $count,
@@ -1102,7 +1102,7 @@ class ShopController extends BaseAuthedController
         $item_id = $goods['goods_id'];
         $item_count = $goods['goods_num'] * $count;
 
-        error_log("buyGoodsDS start " + json_encode(array(
+        error_log("buyGoodsDS start " . json_encode(array(
             'idx' => $idx,
             'grid' => $grid,
             'count' => $count,
@@ -1115,7 +1115,7 @@ class ShopController extends BaseAuthedController
             $item_id,
             $item_count
         );
-        error_log("buyGoodsDS start " + json_encode(array(
+        error_log("buyGoodsDS start " . json_encode(array(
             'idx' => $idx,
             'grid' => $grid,
             'count' => $count,
@@ -1135,7 +1135,7 @@ class ShopController extends BaseAuthedController
             )),
         ));
 
-        error_log("buyGoodsDS start " + json_encode(array(
+        error_log("buyGoodsDS start " . json_encode(array(
             'idx' => $idx,
             'grid' => $grid,
             'count' => $count,