diff --git a/backend/main.py b/backend/main.py
index 231ec9f..170172c 100644
--- a/backend/main.py
+++ b/backend/main.py
@@ -464,6 +464,8 @@ async def create_task(
 @app.get("/api/v1/tasks", response_model=TaskPage)
 async def list_tasks(
     q: str | None = None,
+    list_id: UUID | None = None,
+    completed: bool | None = None,
     cursor: str | None = None,
     limit: int = Query(default=50, ge=1, le=100),
     user: User = Depends(current_user),
@@ -472,6 +474,11 @@ async def list_tasks(
     query = select(Task).where(
         Task.user_id == user.id, Task.deleted_at.is_(None), Task.parent_id.is_(None)
     )
+    if list_id is not None:
+        await _owned_list(db, user.id, list_id)
+        query = query.where(Task.list_id == list_id)
+    if completed is not None:
+        query = query.where(Task.completed.is_(completed))
     if q:
         pattern = f"%{q}%"
         tag_match = exists(
diff --git a/frontend/src/App.vue b/frontend/src/App.vue
index 85f88a0..efafe79 100644
--- a/frontend/src/App.vue
+++ b/frontend/src/App.vue
@@ -35,7 +35,7 @@ const loading = ref(false)
 const mobileSidebar = ref(false)
 const mobileDetail = ref(false)
 const markdownPreview = ref(false)
-const showCompleted = ref(true)
+const showCompleted = ref(false)
 const expandedFolders = ref(new Set<string>())
 
 const activeName = computed(() => {
@@ -70,6 +70,9 @@ watch(query, () => {
   if (activeView.value === 'trash') return
   searchTimer = window.setTimeout(() => loadAll(), 250)
 })
+watch(showCompleted, () => {
+  if (activeView.value !== 'trash') loadAll()
+})
 
 async function api(path: string, options: RequestInit = {}) {
   const response = await fetch('/api/v1' + path, {
@@ -125,12 +128,16 @@ async function loadTaskPages(path: string) {
 async function loadAll() {
   loading.value = true; error.value = ''
   try {
-    const taskPath = query.value ? `/tasks?q=${encodeURIComponent(query.value)}` : '/tasks'
-    const [folderData, listData, tagData, taskData] = await Promise.all([
-      api('/folders'), api('/lists'), api('/tags').catch(() => []), loadTaskPages(taskPath),
+    const [folderData, listData, tagData] = await Promise.all([
+      api('/folders'), api('/lists'), api('/tags').catch(() => []),
     ])
-    folders.value = folderData; lists.value = listData; tags.value = tagData; tasks.value = taskData
+    folders.value = folderData; lists.value = listData; tags.value = tagData
     activeList.value ||= lists.value.find((item) => item.is_inbox)?.id || lists.value[0]?.id || ''
+    const params = new URLSearchParams()
+    if (query.value) params.set('q', query.value)
+    else if (activeView.value === 'tasks' && activeList.value) params.set('list_id', activeList.value)
+    if (!showCompleted.value && activeView.value !== 'trash') params.set('completed', 'false')
+    tasks.value = await loadTaskPages(`/tasks${params.size ? `?${params}` : ''}`)
     expandedFolders.value = new Set(folders.value.map((folder) => folder.id))
   } catch (reason) { fail(reason) } finally { loading.value = false }
 }
@@ -142,6 +149,7 @@ async function switchView(view: View, listId?: string) {
   if (listId) activeList.value = listId
   selectedTask.value = null; selectedIds.value = new Set(); mobileSidebar.value = false; mobileDetail.value = false
   if (view === 'trash') await loadTrash()
+  else await loadAll()
 }
 async function addTask() {
   if (!title.value.trim() || !activeList.value) return
diff --git a/tests/test_mvp_backend.py b/tests/test_mvp_backend.py
index 0dc95ce..338d879 100644
--- a/tests/test_mvp_backend.py
+++ b/tests/test_mvp_backend.py
@@ -107,6 +107,20 @@ def test_attachment_security_ownership_and_size(client, tmp_path, monkeypatch):
     assert client.delete(f"/api/v1/attachments/{attachment['id']}").status_code == 204
 
 
+def test_tasks_can_be_loaded_by_list_and_completion_filter(client):
+    inbox = boot(client)
+    other = client.post("/api/v1/lists", json={"name": "其他清单"}).json()
+    client.post("/api/v1/tasks", json={"title": "收集箱未完成", "list_id": inbox["id"]})
+    done = client.post("/api/v1/tasks", json={"title": "收集箱已完成", "list_id": inbox["id"]}).json()
+    client.patch(f"/api/v1/tasks/{done['id']}", json={"completed": True, "version": done["version"]})
+    client.post("/api/v1/tasks", json={"title": "其他清单未完成", "list_id": other["id"]})
+
+    response = client.get("/api/v1/tasks", params={"list_id": inbox["id"], "completed": False})
+
+    assert response.status_code == 200
+    assert [item["title"] for item in response.json()["items"]] == ["收集箱未完成"]
+
+
 def test_ticktick_preview_import_dedupe_and_json_restore(client):
     boot(client)
     csv_data = "Title,List Name,Due Date,Status,ID\nImported,Inbox,2026-10-01,0,ext-1\n"