diff --git a/CHANGELOG-server.md b/CHANGELOG-server.md
index e46daf1..22d6419 100644
--- a/CHANGELOG-server.md
+++ b/CHANGELOG-server.md
@@ -5,6 +5,11 @@
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.0.77] - 2026-06-22
+
+### 新功能
+- 出库单列表支持按「商品编码」精确反查：可查出包含某个商品编码的所有出库单。同时为出库明细新增 (门店, 商品编码) 复合索引，在数万条明细下仍保持毫秒级查询，不影响写入。
+
 ## [1.0.76] - 2026-06-22
 
 ### 修复
diff --git a/backend/internal/handler/stock_out.go b/backend/internal/handler/stock_out.go
index 1b7cb9c..f23f010 100644
--- a/backend/internal/handler/stock_out.go
+++ b/backend/internal/handler/stock_out.go
@@ -50,6 +50,13 @@ func (h *StockOutHandler) List(c *gin.Context) {
 			like, shopID, like,
 		)
 	}
+	// 按商品编码反查单据：精确匹配，走 idx_so_items_shop_code(shop_id, product_code) 索引
+	if code := strings.TrimSpace(c.Query("product_code")); code != "" {
+		query = query.Where(
+			"id IN (SELECT order_id FROM stock_out_items WHERE shop_id = ? AND product_code = ? AND deleted_at IS NULL)",
+			shopID, code,
+		)
+	}
 
 	var total int64
 	query.Count(&total)
diff --git a/backend/internal/handler/stock_out_test.go b/backend/internal/handler/stock_out_test.go
index ab00688..9187270 100644
--- a/backend/internal/handler/stock_out_test.go
+++ b/backend/internal/handler/stock_out_test.go
@@ -133,6 +133,40 @@ func TestStockOutHandler_List(t *testing.T) {
 	assert.Equal(t, float64(2), resp["total"].(float64))
 }
 
+// 按商品编码精确反查出库单（明细 product_code = ?）
+func TestStockOutHandler_List_FilterByProductCode(t *testing.T) {
+	db := testutil.SetupTestDB()
+	shop := testutil.CreateTestShop(db, "SO_CODE")
+	user := testutil.CreateTestUser(db, shop.ID, "admin", "pass", "admin")
+	warehouse := testutil.CreateTestWarehouse(db, shop.ID, "Warehouse")
+	product := testutil.CreateTestProduct(db, shop.ID, "Beer")
+	token := getAuthToken(user.ID, shop.ID, "admin")
+	r := setupProtectedRouter(db)
+
+	makeRequest(r, "POST", "/api/v1/stock-out/orders", token, map[string]interface{}{
+		"warehouse_id": warehouse.ID, "order_date": time.Now().Format(time.RFC3339),
+		"items": []map[string]interface{}{
+			{"product_id": product.ID, "product_code": "ZXZ-FIND", "quantity": 1.0},
+		},
+	})
+	makeRequest(r, "POST", "/api/v1/stock-out/orders", token, map[string]interface{}{
+		"warehouse_id": warehouse.ID, "order_date": time.Now().Format(time.RFC3339),
+		"items": []map[string]interface{}{
+			{"product_id": product.ID, "product_code": "OTHER-CODE", "quantity": 1.0},
+		},
+	})
+
+	// 精确命中 1 单
+	w := makeRequest(r, "GET", "/api/v1/stock-out/orders?product_code=ZXZ-FIND", token, nil)
+	require.Equal(t, http.StatusOK, w.Code)
+	assert.Equal(t, float64(1), parseResponse(w)["total"].(float64))
+
+	// 不存在的编码 → 0；前缀不算精确（不命中）
+	w = makeRequest(r, "GET", "/api/v1/stock-out/orders?product_code=ZXZ", token, nil)
+	require.Equal(t, http.StatusOK, w.Code)
+	assert.Equal(t, float64(0), parseResponse(w)["total"].(float64))
+}
+
 func TestStockOutHandler_List_FilterByKeyword(t *testing.T) {
 	db := testutil.SetupTestDB()
 	shop := testutil.CreateTestShop(db, "SO011")
diff --git a/backend/main.go b/backend/main.go
index 04f52fb..4e9a7a1 100644
--- a/backend/main.go
+++ b/backend/main.go
@@ -144,5 +144,12 @@ func autoMigrate(db *gorm.DB) {
 			log.Fatalf("create unique index uk_shop_code failed: %v", err)
 		}
 	}
+	// stock_out_items(shop_id, product_code) 复合索引：支撑出库列表「按商品编码反查单据」，
+	// 避免在 2.6 万+ 明细行上全表扫。ShopID 在嵌入字段上无法用 struct tag 表达，故显式幂等建。
+	if !db.Migrator().HasIndex(&model.StockOutItem{}, "idx_so_items_shop_code") {
+		if err := db.Exec("CREATE INDEX idx_so_items_shop_code ON stock_out_items (shop_id, product_code)").Error; err != nil {
+			log.Fatalf("create index idx_so_items_shop_code failed: %v", err)
+		}
+	}
 	log.Println("AutoMigrate completed")
 }
diff --git a/backend/schema/schema.sql b/backend/schema/schema.sql
index e29824a..ab574b7 100644
--- a/backend/schema/schema.sql
+++ b/backend/schema/schema.sql
@@ -369,7 +369,8 @@ CREATE TABLE IF NOT EXISTS `stock_out_items` (
   `remark`       VARCHAR(255)    DEFAULT NULL,
   PRIMARY KEY (`id`),
   KEY `idx_order_id` (`order_id`),
-  KEY `idx_shop_product` (`shop_id`, `product_id`)
+  KEY `idx_shop_product` (`shop_id`, `product_id`),
+  KEY `idx_so_items_shop_code` (`shop_id`, `product_code`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='出库单明细';
 
 -- ------------------------------------------------------------