diff --git a/app/api/logic/LocalStoreGoodsCartLogic.php b/app/api/logic/LocalStoreGoodsCartLogic.php
index 0b999e4c..0f3ccbe7 100644
--- a/app/api/logic/LocalStoreGoodsCartLogic.php
+++ b/app/api/logic/LocalStoreGoodsCartLogic.php
@@ -102,19 +102,28 @@ class LocalStoreGoodsCartLogic extends Logic
                     if ($cart['item_id'] == 0) {
                         // 单规格商品
                         $item = LocalStoreGoods::where('id', $cart['lsg_id'])->field('price')->find();
-                        if ($cart['goods_num'] + $post['goods_num'] > 999) {
+                        if ($post['type'] == 'plus' && $cart['goods_num'] + $post['goods_num'] > 999) {
                             throw new \Exception('商品数量超出限制');
                         }
                     } else {
                         // 多规格商品
                         $item = LocalStoreGoodsItem::where('id', $cart['item_id'])->field('price, stock')->find();
-                        if ($cart['goods_num'] + $post['goods_num'] > $item['stock']) {
+                        if ($post['type'] == 'plus' && $cart['goods_num'] + $post['goods_num'] > $item['stock']) {
                             throw new \Exception('商品数量超出限制');
                         }
                     }
 
-                    $price = number_format($post['goods_num'] * $item['price'], 2, '.', '');
-                    $goods_num = $cart['goods_num'] + $post['goods_num'];
+                    if ($post['type'] == 'minus') {
+                        $goods_num = $cart['goods_num'] - $post['goods_num'];
+                    } else {
+                        $goods_num = $cart['goods_num'] + $post['goods_num'];
+                    }
+
+                    if ($goods_num <= 0) {
+                        throw new \Exception('商品数量不能小于0');
+                    }
+
+                    $price = number_format($goods_num * $item['price'], 2, '.', '');
 
                     LocalStoreGoodsCart::where('id', $post['cart_id'])->update([
                         'goods_num' => $goods_num