diff --git a/qcloudcos/cosapi.php b/qcloudcos/cosapi.php
index 8c440b2..6f80d13 100644
--- a/qcloudcos/cosapi.php
+++ b/qcloudcos/cosapi.php
@@ -355,7 +355,7 @@ private static function uploadBySlicing(
 
         return array(
                     'code' => 0,
-                    'message' => 'success',
+                    'message' => 'SUCCESS',
                     'request_id' => $sliceUploading->getRequestId(),
                     'data' => array(
                         'access_url' => $sliceUploading->getAccessUrl(),
diff --git a/qcloudcos/slice_uploading.php b/qcloudcos/slice_uploading.php
index dd1b0ca..d5fb57c 100644
--- a/qcloudcos/slice_uploading.php
+++ b/qcloudcos/slice_uploading.php
@@ -230,7 +230,7 @@ private function sendRequest($request) {
 
     private function clearError() {
         $this->errorCode = COSAPI_SUCCESS;
-        $this->errorMessage = 'success';
+        $this->errorMessage = 'SUCCESS';
     }
 
     private function setError($errorCode, $errorMessage) {
@@ -244,7 +244,7 @@ public function uploadCallback($request, $response) {
         }
 
         $requestErrorCode = COSAPI_SUCCESS;
-        $requestErrorMessage = 'success';
+        $requestErrorMessage = 'SUCCESS';
         $retryCount = $request->userData['retryCount'];
 
         $responseJson = json_decode($response->body, true);