diff --git a/wx/V3/WxV3AppPayment.php b/wx/V3/WxV3AppPayment.php
index 5f1f016..e2706af 100644
--- a/wx/V3/WxV3AppPayment.php
+++ b/wx/V3/WxV3AppPayment.php
@@ -20,7 +20,7 @@ class WxV3AppPayment extends SmallProgram
      * @return array
      * @throws
      */
-    public function payment(string $orderNo, int $total, string $openId = NULL, string $payer_client_ip = '127.0.0.1'): array
+    public function payment(string $orderNo, int $total, ?string $openId = NULL, string $payer_client_ip = '127.0.0.1'): array
     {
         $body = $this->getInitCore($orderNo, $total);
 
diff --git a/wx/V3/WxV3NativePayment.php b/wx/V3/WxV3NativePayment.php
index 9e02e00..2850462 100644
--- a/wx/V3/WxV3NativePayment.php
+++ b/wx/V3/WxV3NativePayment.php
@@ -22,7 +22,7 @@ class WxV3NativePayment extends SmallProgram
      * @throws
      */
     #[ArrayShape(['code_url' => "string"])]
-    public function payment(string $orderNo, int $total, string $openId = NULL, string $payer_client_ip = '127.0.0.1'): array
+    public function payment(string $orderNo, int $total, ?string $openId = NULL, string $payer_client_ip = '127.0.0.1'): array
     {
         $body = $this->getInitCore($orderNo, $total);
 
diff --git a/wx/V3/WxV3Payment.php b/wx/V3/WxV3Payment.php
index 0d51515..890ba8d 100644
--- a/wx/V3/WxV3Payment.php
+++ b/wx/V3/WxV3Payment.php
@@ -20,7 +20,7 @@ class WxV3Payment extends SmallProgram
      * @return array
      * @throws
      */
-    public function payment(string $orderNo, int $total, string $openId = NULL, string $payer_client_ip = '127.0.0.1'): array
+    public function payment(string $orderNo, int $total, ?string $openId = NULL, string $payer_client_ip = '127.0.0.1'): array
     {
         $body               = $this->getInitCore($orderNo, $total);
         $body['payer']      = ['openid' => $openId];