diff --git a/waynboot-mobile-api/src/main/java/com/wayn/mobile/api/controller/CartController.java b/waynboot-mobile-api/src/main/java/com/wayn/mobile/api/controller/CartController.java
index 3fbb33a..ee5e9e4 100644
--- a/waynboot-mobile-api/src/main/java/com/wayn/mobile/api/controller/CartController.java
+++ b/waynboot-mobile-api/src/main/java/com/wayn/mobile/api/controller/CartController.java
@@ -44,6 +44,11 @@ public class CartController extends BaseController {
         return R.result(iCartService.updateById(cart));
     }
 
+    @PostMapping("changeNum/{cartId}/{number}")
+    public R changeNum(@PathVariable Long cartId, @PathVariable Integer number) {
+        return iCartService.changeNum(cartId, number);
+    }
+
     @PostMapping("addNum/{cartId}/{number}")
     public R addNum(@PathVariable Long cartId, @PathVariable Integer number) {
         return iCartService.addNum(cartId, number);
diff --git a/waynboot-mobile-api/src/main/java/com/wayn/mobile/api/service/ICartService.java b/waynboot-mobile-api/src/main/java/com/wayn/mobile/api/service/ICartService.java
index a24d725..9fab64e 100644
--- a/waynboot-mobile-api/src/main/java/com/wayn/mobile/api/service/ICartService.java
+++ b/waynboot-mobile-api/src/main/java/com/wayn/mobile/api/service/ICartService.java
@@ -16,6 +16,7 @@ public interface ICartService extends IService<Cart> {
 
     /**
      * 检查用户购物车中是否有商品货品
+     *
      * @param userId
      * @param goodsId
      * @param productId
@@ -36,18 +37,43 @@ public interface ICartService extends IService<Cart> {
 
     /**
      * 计算购物车中商品数量
+     *
      * @return R
      */
     R goodsCount();
 
     /**
      * 查询用户购物车商品
+     *
      * @param userId 用户ID
      * @return R
      */
     R list(Long userId);
 
+    /**
+     * 改变购物车商品数量
+     *
+     * @param cartId 购物车商品ID
+     * @param number 商品数量
+     * @return r
+     */
+    R changeNum(Long cartId, Integer number);
+
+    /**
+     * 添加购物车商品数量
+     *
+     * @param cartId 购物车商品ID
+     * @param number 商品数量
+     * @return r
+     */
     R addNum(Long cartId, Integer number);
 
+    /**
+     * 减少购物车商品数量
+     *
+     * @param cartId 购物车商品ID
+     * @param number 商品数量
+     * @return r
+     */
     R minusNum(Long cartId, Integer number);
 }
diff --git a/waynboot-mobile-api/src/main/java/com/wayn/mobile/api/service/impl/CartServiceImpl.java b/waynboot-mobile-api/src/main/java/com/wayn/mobile/api/service/impl/CartServiceImpl.java
index 4e64d43..12c390a 100644
--- a/waynboot-mobile-api/src/main/java/com/wayn/mobile/api/service/impl/CartServiceImpl.java
+++ b/waynboot-mobile-api/src/main/java/com/wayn/mobile/api/service/impl/CartServiceImpl.java
@@ -111,6 +111,11 @@ public class CartServiceImpl extends ServiceImpl<CartMapper, Cart> implements IC
         return R.success().add("data", cartList);
     }
 
+    @Override
+    public R changeNum(Long cartId, Integer number) {
+        return R.result(update().setSql("number = " + number).eq("id", cartId).update(), "修改失败");
+    }
+
     @Override
     public R addNum(Long cartId, Integer number) {
         return R.result(update().setSql("number = number + 1").eq("id", cartId).update(), "添加失败");