diff --git a/src/Drivers/AliyunDriver.php b/src/Drivers/AliyunDriver.php
index 596b02e..1be5f41 100644
--- a/src/Drivers/AliyunDriver.php
+++ b/src/Drivers/AliyunDriver.php
@@ -65,7 +65,7 @@ protected function generateSign(array $params): string
     {
         ksort($params);
         $accessKeySecret = $this->config->get('access_key_secret');
-        $stringToSign = 'GET&%2F&' . urlencode(http_build_query($params, null, '&', PHP_QUERY_RFC3986));
+        $stringToSign = 'GET&%2F&' . urlencode(http_build_query($params, '', '&', PHP_QUERY_RFC3986));
 
         return base64_encode(hash_hmac('sha1', $stringToSign, $accessKeySecret . '&', true));
     }