diff --git a/src/Qiniu/Config.php b/src/Qiniu/Config.php
index 3ce7fa5a..cf1a72be 100644
--- a/src/Qiniu/Config.php
+++ b/src/Qiniu/Config.php
@@ -41,7 +41,7 @@ final class Config
     public $backupUcHostsRetryTimes;
 
     // 构造函数
-    public function __construct(Region $z = null)
+    public function __construct(?Region $z = null)
     {
         $this->zone = $z;
         $this->useHTTPS = false;
diff --git a/src/Qiniu/Storage/ArgusManager.php b/src/Qiniu/Storage/ArgusManager.php
index 51b4200c..f2da782a 100644
--- a/src/Qiniu/Storage/ArgusManager.php
+++ b/src/Qiniu/Storage/ArgusManager.php
@@ -22,7 +22,7 @@ final class ArgusManager
 
     public function __construct(
         Auth $auth,
-        Config $config = null,
+        ?Config $config = null,
         $proxy = null,
         $proxy_auth = null,
         $proxy_user_password = null
diff --git a/src/Qiniu/Storage/BucketManager.php b/src/Qiniu/Storage/BucketManager.php
index bfca4fc1..809523b7 100644
--- a/src/Qiniu/Storage/BucketManager.php
+++ b/src/Qiniu/Storage/BucketManager.php
@@ -22,7 +22,7 @@ final class BucketManager
 
     public function __construct(
         Auth $auth,
-        Config $config = null,
+        ?Config $config = null,
         $proxy = null,
         $proxy_auth = null,
         $proxy_user_password = null
diff --git a/src/Qiniu/Storage/UploadManager.php b/src/Qiniu/Storage/UploadManager.php
index fcd11fad..c91a2db6 100644
--- a/src/Qiniu/Storage/UploadManager.php
+++ b/src/Qiniu/Storage/UploadManager.php
@@ -24,7 +24,7 @@ final class UploadManager
      * @param Config|null $config
      * @param RequestOptions|null $reqOpt
      */
-    public function __construct(Config $config = null, RequestOptions $reqOpt = null)
+    public function __construct(?Config $config = null, ?RequestOptions $reqOpt = null)
     {
         if ($config === null) {
             $config = new Config();