diff --git a/src/main/java/com/chaozhanggui/system/cashierservice/service/PayService.java b/src/main/java/com/chaozhanggui/system/cashierservice/service/PayService.java
index de45ae3..069540e 100644
--- a/src/main/java/com/chaozhanggui/system/cashierservice/service/PayService.java
+++ b/src/main/java/com/chaozhanggui/system/cashierservice/service/PayService.java
@@ -460,6 +460,9 @@ public class PayService {
             }
 
             shouldPayAmount = shouldPayAmount.subtract(userCouponVo.getDiscountAmount());
+            if (shouldPayAmount.compareTo(BigDecimal.ZERO) < 0) {
+                shouldPayAmount = new BigDecimal("0.01");
+            }
 
             TbShopCoupon tbShopCoupons = mpShopCouponMapper.selectById(userCouponVo.getCouponId());
             if (tbShopCoupons == null) {