diff --git a/backend/src/services/commissionService.js b/backend/src/services/commissionService.js
index f48c3d3..e8e5442 100644
--- a/backend/src/services/commissionService.js
+++ b/backend/src/services/commissionService.js
@@ -37,8 +37,11 @@ const calculateCommission = async (paymentOrderId) => {
   // Get current commission rate
   const commissionRate = await commissionConfigService.getCommissionRate();
 
-  // Calculate commission amount
-  const paymentAmount = parseFloat(paymentOrder.amount);
+  // Calculate commission amount - use amountRmb if available, otherwise use amount
+  const paymentAmount = parseFloat(paymentOrder.amountRmb || paymentOrder.amount || 0);
+  if (paymentAmount <= 0) {
+    return null; // No valid payment amount
+  }
   const commissionAmount = paymentAmount * commissionRate;
 
   // Start transaction