diff --git a/app/Services/Refund.php b/app/Services/Refund.php
index 8de8a5e3..90d66b1d 100644
--- a/app/Services/Refund.php
+++ b/app/Services/Refund.php
@@ -174,10 +174,10 @@ class Refund extends Service
 
         switch ($trade->channel) {
             case TradeModel::CHANNEL_ALIPAY:
-                $serviceRate = $alipay['service_rate'] ?: $serviceRate;
+                $serviceRate = $alipay['service_rate'] ?? $serviceRate;
                 break;
             case TradeModel::CHANNEL_WXPAY:
-                $serviceRate = $wxpay['service_rate'] ?: $serviceRate;
+                $serviceRate = $wxpay['service_rate'] ?? $serviceRate;
                 break;
         }