diff --git a/frontend/src/stores/stock.js b/frontend/src/stores/stock.js
index 8e8ad94d..ea9b6a8a 100644
--- a/frontend/src/stores/stock.js
+++ b/frontend/src/stores/stock.js
@@ -14,7 +14,12 @@ export const useStockStore = defineStore('stock', () => {
   // 入库表单还要读预警阈值，共用同一份缓存避免重复请求。
   const stockCache = ref({})
 
+  // 列表当前生效的筛选条件。保存预警之类的操作会在原地重新拉取列表，那次拉取必须
+  // 沿用它们，否则列表会悄悄退回全量，而下拉框里还显示着用户选中的筛选值。
+  const stockFilters = ref({ search: '', category: '' })
+
   async function fetchStock(page = 1, search = '', category = '') {
+    stockFilters.value = { search, category }
     loading.value = true
     try {
       const pageSize = stockPage.value.pageSize
@@ -105,7 +110,7 @@ export const useStockStore = defineStore('stock', () => {
     // 阈值改了，单物料缓存里的旧值必须作废，否则入库表单会预填到过期数据。
     delete stockCache.value[materialId]
     await Promise.all([
-      fetchStock(stockPage.value.currentPage),
+      fetchStock(stockPage.value.currentPage, stockFilters.value.search, stockFilters.value.category),
       fetchStockWarning(warningPage.value.currentPage)
     ])
   }
diff --git a/frontend/src/stores/stock.test.js b/frontend/src/stores/stock.test.js
index 757265a7..a157af73 100644
--- a/frontend/src/stores/stock.test.js
+++ b/frontend/src/stores/stock.test.js
@@ -59,6 +59,34 @@ describe('stock store warning settings', () => {
     expect(quantity).toBe('12.500000')
   })
 
+  // 保存预警会在原地重新拉取列表，那次拉取必须沿用用户当前的筛选条件：否则列表会
+  // 悄悄退回全量，而下拉框里还显示着选中的分类，用户以为筛选还在生效。
+  it('保存预警后刷新列表要沿用当前的筛选条件', async () => {
+    const store = useStockStore()
+
+    await store.fetchStock(1, '轴承', 'A01')
+    stockApi.getAll.mockClear()
+
+    await store.updateWarningStock(1, 8)
+
+    expect(stockApi.getAll).toHaveBeenCalledWith(
+      expect.objectContaining({ search: '轴承', category: 'A01' })
+    )
+  })
+
+  // 首次加载没有筛选条件，别把上一次的筛选状态带到新页面上。
+  it('不带筛选条件地重新查询会清掉旧的筛选状态', async () => {
+    const store = useStockStore()
+
+    await store.fetchStock(1, '轴承', 'A01')
+    stockApi.getAll.mockClear()
+    await store.fetchStock(1)
+
+    expect(stockApi.getAll).toHaveBeenCalledWith(
+      expect.objectContaining({ search: '', category: '' })
+    )
+  })
+
   // 入库表单选物料时会为了预填预警值而查询库存，顺手把当时（入库前）的数量缓存下来。
   // 入库保存后库存已经变了，缓存若不失效，出库表单会一直显示入库前的旧数字，
   // 用户得刷新页面才能看到正确值。
diff --git a/frontend/src/views/Stock.test.js b/frontend/src/views/Stock.test.js
index 8bb06379..02bcb92f 100644
--- a/frontend/src/views/Stock.test.js
+++ b/frontend/src/views/Stock.test.js
@@ -123,3 +123,45 @@ describe('库存预警阈值校验', () => {
     wrapper.unmount()
   })
 })
+
+describe('库存分类筛选', () => {
+  beforeEach(() => {
+    stockStore.fetchStock.mockReset()
+    stockStore.fetchStockLogs.mockReset()
+    stockStore.fetchStockWarning.mockReset()
+    materialsStore.fetchMaterialOptions.mockReset()
+    materialsStore.fetchHistoricalMaterialOptions.mockReset()
+  })
+
+  // 选中的大类要跟着查询一起发给 store，否则后端收不到 category、条件被静默丢弃，
+  // 用户点「查询」看起来毫无反应。
+  test('选中的大类随查询一起发给 store', async () => {
+    const wrapper = mountStock()
+    await flushPromises()
+
+    wrapper.vm.$.setupState.categoryFilter = 'A01'
+    await flushPromises()
+
+    stockStore.fetchStock.mockClear()
+    await findButton(wrapper, '查询').trigger('click')
+
+    expect(stockStore.fetchStock).toHaveBeenCalledWith(1, '', 'A01')
+    wrapper.unmount()
+  })
+
+  // 翻页同样要带着筛选条件，否则第 2 页会退回全量数据。
+  test('翻页时也带着分类筛选', async () => {
+    const wrapper = mountStock()
+    await flushPromises()
+
+    wrapper.vm.$.setupState.categoryFilter = 'A01'
+    await flushPromises()
+
+    stockStore.fetchStock.mockClear()
+    wrapper.vm.$.setupState.handlePageChange(2)
+    await flushPromises()
+
+    expect(stockStore.fetchStock).toHaveBeenCalledWith(2, '', 'A01')
+    wrapper.unmount()
+  })
+})
diff --git a/internal/handler/api.go b/internal/handler/api.go
index d7b9a94c..f7f8c8b4 100644
--- a/internal/handler/api.go
+++ b/internal/handler/api.go
@@ -737,8 +737,10 @@ func (h *Handler) ListStock(c *gin.Context) {
 	}
 
 	search := c.Query("search")
+	// 大类编码筛选，前端下拉选中的就是 material_categories 里的大类 code
+	category := c.Query("category")
 
-	stocks, total, err := h.stockSvc.GetAllStock(search, limit, offset)
+	stocks, total, err := h.stockSvc.GetAllStock(search, category, limit, offset)
 	if err != nil {
 		response.InternalError(c, err.Error())
 		return
diff --git a/internal/repository/stock.go b/internal/repository/stock.go
index c5523955..ec0b8f95 100644
--- a/internal/repository/stock.go
+++ b/internal/repository/stock.go
@@ -44,8 +44,16 @@ func NewStockRepo() *StockRepo {
 	return &StockRepo{}
 }
 
-func (r *StockRepo) GetAllStock(search string, limit, offset int) ([]model.Stock, int64, error) {
-	countQuery := `SELECT COUNT(*) FROM materials m WHERE 1=1` + stockedMaterialFilterSQL
+// GetAllStock 的 category 收的是大类编码（material_categories 里 parent_id 为空的那层）。
+// 按大类 code 而不是 category_id 过滤，是为了和前端下拉直接选出的大类选项对上。
+func (r *StockRepo) GetAllStock(search, category string, limit, offset int) ([]model.Stock, int64, error) {
+	// COUNT 和主查询是两条独立 SQL，筛选条件必须成对出现，否则分页总数会和实际行数
+	// 对不上、末尾多出空白页。主查询本来就 JOIN 了分类表，这里为按大类过滤补上同样的 JOIN；
+	// 两张表都按主键关联，不会放大行数，COUNT 的语义不变。
+	countQuery := `SELECT COUNT(*) FROM materials m
+		LEFT JOIN material_categories c ON c.id = m.category_id
+		LEFT JOIN material_categories pc ON pc.id = c.parent_id
+		WHERE 1=1` + stockedMaterialFilterSQL
 	var countArgs []interface{}
 
 	if search != "" {
@@ -53,6 +61,10 @@ func (r *StockRepo) GetAllStock(search string, limit, offset int) ([]model.Stock
 		searchPattern := "%" + search + "%"
 		countArgs = append(countArgs, searchPattern, searchPattern)
 	}
+	if category != "" {
+		countQuery += ` AND pc.code = ?`
+		countArgs = append(countArgs, category)
+	}
 
 	var total int64
 	err := database.DB.QueryRow(countQuery, countArgs...).Scan(&total)
@@ -78,6 +90,10 @@ func (r *StockRepo) GetAllStock(search string, limit, offset int) ([]model.Stock
 		searchPattern := "%" + search + "%"
 		args = append(args, searchPattern, searchPattern)
 	}
+	if category != "" {
+		query += ` AND pc.code = ?`
+		args = append(args, category)
+	}
 
 	query += ` GROUP BY m.id, m.material_code, m.name, m.spec, m.unit, pc.code, c.code ORDER BY m.id LIMIT ? OFFSET ?`
 	args = append(args, limit, offset)
diff --git a/internal/repository/stock_test.go b/internal/repository/stock_test.go
index f8ea63cf..3274f631 100644
--- a/internal/repository/stock_test.go
+++ b/internal/repository/stock_test.go
@@ -246,7 +246,7 @@ func TestStockRepoGetAllStockFiltersBothCountAndList(t *testing.T) {
 	database.DB = db
 
 	filter := regexp.QuoteMeta(stockedMaterialFilterSQL)
-	mock.ExpectQuery(`(?s)SELECT COUNT\(\*\) FROM materials m WHERE 1=1.*` + filter).
+	mock.ExpectQuery(`(?s)SELECT COUNT\(\*\) FROM materials m.*` + filter).
 		WillReturnRows(sqlmock.NewRows([]string{"count"}).AddRow(1))
 	mock.ExpectQuery(`(?s)SELECT m\.id, m\.material_code.*`+filter+`.*ORDER BY m\.id LIMIT \? OFFSET \?`).
 		WithArgs(20, 0).
@@ -254,7 +254,7 @@ func TestStockRepoGetAllStockFiltersBothCountAndList(t *testing.T) {
 			"id", "material_code", "name", "spec", "unit", "on_hand", "minimum_available", "enabled", "warning_configured", "major_category", "minor_category",
 		}).AddRow(7, "MAT-007", "轴承", "6204", "个", "4.000000", "10.000000", true, true, "A01", "A01-01"))
 
-	stocks, total, err := NewStockRepo().GetAllStock("", 20, 0)
+	stocks, total, err := NewStockRepo().GetAllStock("", "", 20, 0)
 	if err != nil {
 		t.Fatalf("get all stock: %v", err)
 	}
@@ -269,6 +269,45 @@ func TestStockRepoGetAllStockFiltersBothCountAndList(t *testing.T) {
 	}
 }
 
+// 大类筛选同样要成对落到 COUNT 和主查询上，参数顺序也得与占位符一致：只改一边的话，
+// 筛选后的列表会配上一个没筛选的总数，翻到最后一页只会看到空白。
+func TestStockRepoGetAllStockAppliesCategoryToBothQueries(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	if err != nil {
+		t.Fatalf("open sql mock: %v", err)
+	}
+	t.Cleanup(func() {
+		database.DB = nil
+		db.Close()
+	})
+	database.DB = db
+
+	filter := regexp.QuoteMeta(stockedMaterialFilterSQL)
+	// 主查询本来就 JOIN 了分类表，COUNT 那条也必须补上，否则拿 pc.code 过滤会直接报未知列
+	mock.ExpectQuery(`(?s)SELECT COUNT\(\*\) FROM materials m.*LEFT JOIN material_categories pc.*` + filter + `.*AND pc\.code = \?`).
+		WithArgs("A01").
+		WillReturnRows(sqlmock.NewRows([]string{"count"}).AddRow(1))
+	mock.ExpectQuery(`(?s)SELECT m\.id, m\.material_code.*` + filter + `.*AND pc\.code = \?.*ORDER BY m\.id LIMIT \? OFFSET \?`).
+		WithArgs("A01", 20, 0).
+		WillReturnRows(sqlmock.NewRows([]string{
+			"id", "material_code", "name", "spec", "unit", "on_hand", "minimum_available", "enabled", "warning_configured", "major_category", "minor_category",
+		}).AddRow(7, "MAT-007", "轴承", "6204", "个", "4.000000", "10.000000", true, true, "A01", "A01-01"))
+
+	stocks, total, err := NewStockRepo().GetAllStock("", "A01", 20, 0)
+	if err != nil {
+		t.Fatalf("get all stock by category: %v", err)
+	}
+	if total != 1 || len(stocks) != 1 {
+		t.Fatalf("unexpected result: total=%d stocks=%+v", total, stocks)
+	}
+	if stocks[0].MajorCategory != "A01" {
+		t.Fatalf("unexpected major category: %+v", stocks[0])
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Fatal(err)
+	}
+}
+
 // 预警列表同样有 COUNT 和主查询两条 SQL，而且两条都必须带上与 service.ClassifyStock
 // 对应的 HAVING 判定。
 func TestStockRepoGetWarningStockAppliesThresholdRuleToBothQueries(t *testing.T) {
diff --git a/internal/service/stock.go b/internal/service/stock.go
index 3c0ff1c3..9653b170 100644
--- a/internal/service/stock.go
+++ b/internal/service/stock.go
@@ -40,8 +40,8 @@ func classifyAll(stocks []model.Stock) {
 	}
 }
 
-func (s *StockService) GetAllStock(search string, limit, offset int) ([]model.Stock, int64, error) {
-	stocks, total, err := s.stockRepo.GetAllStock(search, limit, offset)
+func (s *StockService) GetAllStock(search, category string, limit, offset int) ([]model.Stock, int64, error) {
+	stocks, total, err := s.stockRepo.GetAllStock(search, category, limit, offset)
 	if err != nil {
 		return nil, 0, err
 	}