diff --git a/ebike-feign/src/main/java/com/ebike/feign/model/dto/FeignEbikePaymentAmountDto.java b/ebike-feign/src/main/java/com/ebike/feign/model/dto/FeignEbikePaymentAmountDto.java
index e6dad84..7e61e2a 100644
--- a/ebike-feign/src/main/java/com/ebike/feign/model/dto/FeignEbikePaymentAmountDto.java
+++ b/ebike-feign/src/main/java/com/ebike/feign/model/dto/FeignEbikePaymentAmountDto.java
@@ -1,5 +1,6 @@
 package com.ebike.feign.model.dto;
 
+import jakarta.validation.constraints.DecimalMin;
 import jakarta.validation.constraints.NotBlank;
 import jakarta.validation.constraints.NotNull;
 import lombok.AllArgsConstructor;
@@ -22,6 +23,7 @@ public class FeignEbikePaymentAmountDto {
     @NotBlank(message = "车辆编号不能为空")
     private String bikeCode;
 
+    @DecimalMin(value = "0.00", message = "修改后的价格不能小于0")
     @NotNull(message = "价格不能为空")
     private BigDecimal price;
 }
diff --git a/ebike-user/src/main/java/com/cdzy/user/service/impl/EbikeOrderServiceImpl.java b/ebike-user/src/main/java/com/cdzy/user/service/impl/EbikeOrderServiceImpl.java
index 5636450..ef8067c 100644
--- a/ebike-user/src/main/java/com/cdzy/user/service/impl/EbikeOrderServiceImpl.java
+++ b/ebike-user/src/main/java/com/cdzy/user/service/impl/EbikeOrderServiceImpl.java
@@ -338,6 +338,7 @@ public class EbikeOrderServiceImpl extends ServiceImpl<EbikeOrderMapper, EbikeOr
     @Transactional
     @Override
     public void updateOrderAmount(FeignEbikePaymentAmountDto paymentAmountDto) {
+        BigDecimal newPrice = paymentAmountDto.getPrice();
         // 1 获取当前车辆未支付的订单
         QueryWrapper queryWrapper = QueryWrapper.create()
                 .select(EBIKE_ORDER.ALL_COLUMNS)
@@ -345,25 +346,15 @@ public class EbikeOrderServiceImpl extends ServiceImpl<EbikeOrderMapper, EbikeOr
                 .where(EBIKE_ORDER.ORDER_STATUS.eq(OrderStatus.PENDING_PAYMENT));
         EbikeOrder ebikeOrder = this.mapper.selectOneByQuery(queryWrapper);
         if (Objects.isNull(ebikeOrder)) {
-            throw new EbikeException("当前车辆不存在待支付的订单");
+            throw new EbikeException("当前车辆不存在待支付的订单,或订单已被处理");
+        }
+        if (newPrice.compareTo(BigDecimal.ZERO) == 0) {
+            log.info("开始处理免费订单，订单id:{}", ebikeOrder.getOrderId());
+            handleFreeOrder(ebikeOrder);
+        } else {
+            log.info("开始处理非免费订单，订单id:{}", ebikeOrder.getOrderId());
+            handlePriceChange(ebikeOrder, newPrice);
         }
-        // 2 修改当前订单金额(实付金额)
-        UpdateChain.of(EbikeOrder.class)
-                .set(EbikeOrder::getActualAmount, paymentAmountDto.getPrice())
-                .where(EbikeOrder::getOrderId).eq(ebikeOrder.getOrderId())
-                .update();
-        // 3 同步修改支付订单的cost_price(用于支付时的实际金额)
-        ebikePaymentService.updateCostPrice(ebikeOrder.getOrderId(), paymentAmountDto.getPrice());
-        // 4 生成订单明细优惠金额
-        EbikeOrderDetail orderDetail = EbikeOrderDetail.builder()
-                .orderId(ebikeOrder.getOrderId())
-                .operatorId(ebikeOrder.getOperatorId())
-                .detailType(EbikeOrderDetailType.DISCOUNT_AMOUNT.getCode())
-                .detailDescription("运维人员修改订单减免金额")
-                .detailName(EbikeOrderDetailType.DISCOUNT_AMOUNT.getName())
-                .detailAmount(ebikeOrder.getTotalAmount().subtract(paymentAmountDto.getPrice()))
-                .build();
-        ebikeOrderDetailService.save(orderDetail);
     }
 
     @Transactional
@@ -434,6 +425,63 @@ public class EbikeOrderServiceImpl extends ServiceImpl<EbikeOrderMapper, EbikeOr
         return this.mapper.paginateAs(pageParam, queryWrapper, EbikeDiffOperatorOrderListVo.class);
     }
 
+    /**
+     * 处理改价逻辑
+     */
+    private void handlePriceChange(EbikeOrder order, BigDecimal newPrice) {
+        long orderId = order.getOrderId();
+        BigDecimal totalAmount = order.getTotalAmount();
+
+        // 1. 更新订单实付金额
+        UpdateChain.of(EbikeOrder.class)
+                .set(EbikeOrder::getActualAmount, newPrice)
+                .where(EbikeOrder::getOrderId).eq(orderId)
+                .where(EbikeOrder::getOrderStatus).eq(OrderStatus.PENDING_PAYMENT)
+                .update();
+
+        // 2. 同步修改支付表的 cost_price
+        ebikePaymentService.updateCostPrice(orderId, newPrice);
+
+        // 3. 生成优惠明细
+        BigDecimal discountAmount = totalAmount.subtract(newPrice);
+        if (discountAmount.compareTo(BigDecimal.ZERO) > 0) {
+            saveDiscountDetail(order, discountAmount, "运维人员修改订单减免金额");
+        }
+    }
+
+    /**
+     * 处理免费订单逻辑
+     */
+    private void handleFreeOrder(EbikeOrder order) {
+        // 1. 更新订单状态
+        order.setOrderStatus(OrderStatus.PAID);
+        order.setActualAmount(BigDecimal.ZERO);
+        order.setPaymentTime(LocalDateTime.now());
+        order.setIsFreeOrder(Boolean.TRUE);
+        this.updateById(order);
+        // 2. 逻辑删除支付记录
+        EbikePayment payment = ebikePaymentService.queryPaymentInfo(order.getOrderId());
+        ebikePaymentService.removeById(payment);
+        // 3. 记录优惠明细
+        saveDiscountDetail(order, order.getTotalAmount(), "全额减免");
+    }
+
+    /**
+     * 保存优惠明细
+     */
+    private void saveDiscountDetail(EbikeOrder order, BigDecimal amount, String description) {
+        EbikeOrderDetail detail = EbikeOrderDetail.builder()
+                .orderId(order.getOrderId())
+                .operatorId(order.getOperatorId())
+                .detailType(EbikeOrderDetailType.DISCOUNT_AMOUNT.getCode())
+                .detailDescription(description)
+                .detailName(EbikeOrderDetailType.DISCOUNT_AMOUNT.getName())
+                .detailAmount(amount)
+                .createTime(LocalDateTime.now())
+                .build();
+        ebikeOrderDetailService.save(detail);
+    }
+
     /**
      * 计算增长率并格式化为百分比字符串
      *