diff --git a/web/hwlab-cloud-web/src/utils/tasktree-route-loader.test.ts b/web/hwlab-cloud-web/src/utils/tasktree-route-loader.test.ts
new file mode 100644
index 00000000..ea347536
--- /dev/null
+++ b/web/hwlab-cloud-web/src/utils/tasktree-route-loader.test.ts
@@ -0,0 +1,28 @@
+import { describe, expect, it, vi } from "vitest";
+
+import { loadTaskTreeRoute } from "./tasktree-route-loader";
+
+describe("loadTaskTreeRoute", () => {
+  it("loads only the global overview for the TaskTree root route", async () => {
+    const overview = vi.fn().mockResolvedValue({ ok: true });
+    const timeline = vi.fn();
+
+    const result = await loadTaskTreeRoute({ overview, timeline }, "");
+
+    expect(result.view).toBe("global");
+    expect(overview).toHaveBeenCalledOnce();
+    expect(timeline).not.toHaveBeenCalled();
+  });
+
+  it("loads a group timeline without depending on the global overview", async () => {
+    const overview = vi.fn();
+    const timeline = vi.fn().mockResolvedValue({ ok: true });
+
+    const result = await loadTaskTreeRoute({ overview, timeline }, "tg_example");
+
+    expect(result.view).toBe("group");
+    expect(timeline).toHaveBeenCalledOnce();
+    expect(timeline).toHaveBeenCalledWith("tg_example");
+    expect(overview).not.toHaveBeenCalled();
+  });
+});
diff --git a/web/hwlab-cloud-web/src/utils/tasktree-route-loader.ts b/web/hwlab-cloud-web/src/utils/tasktree-route-loader.ts
new file mode 100644
index 00000000..57cebe88
--- /dev/null
+++ b/web/hwlab-cloud-web/src/utils/tasktree-route-loader.ts
@@ -0,0 +1,10 @@
+import type { tasktreeAPI } from "@/api/tasktree";
+
+type TaskTreeReadApi = Pick<typeof tasktreeAPI, "overview" | "timeline">;
+
+export async function loadTaskTreeRoute(api: TaskTreeReadApi, groupId: string) {
+  if (groupId) {
+    return { view: "group" as const, response: await api.timeline(groupId) };
+  }
+  return { view: "global" as const, response: await api.overview() };
+}
diff --git a/web/hwlab-cloud-web/src/views/projects/TaskTreeView.vue b/web/hwlab-cloud-web/src/views/projects/TaskTreeView.vue
index 1959f63c..e10a8ed0 100644
--- a/web/hwlab-cloud-web/src/views/projects/TaskTreeView.vue
+++ b/web/hwlab-cloud-web/src/views/projects/TaskTreeView.vue
@@ -9,6 +9,7 @@ import TaskTreeDetailPanel from "@/components/tasktree/TaskTreeDetailPanel.vue";
 import MessageMarkdown from "@/components/workbench/MessageMarkdown.vue";
 import { displayTimeConfig } from "@/config/runtime";
 import { decideNestedWheelBoundary, type NestedWheelBoundaryState } from "@/utils/nested-wheel-boundary";
+import { loadTaskTreeRoute } from "@/utils/tasktree-route-loader";
 import { deriveEffectiveTaskTimeRanges } from "@/utils/tasktree-time-range";
 
 const route = useRoute();
@@ -108,32 +109,37 @@ watch(requestedDetailMode, (mode) => { detailMode.value = mode; });
 
 async function loadActiveView() {
   loading.value = true; error.value = null;
-  const overviewResponse = await tasktreeAPI.overview();
-  if (!overviewResponse.ok || overviewResponse.data?.ok === false) {
-    loading.value = false;
-    error.value = overviewResponse.data?.error?.message || overviewResponse.error || "TaskTree 全局视图加载失败";
-    return;
-  }
-  overview.value = overviewResponse.data?.data?.groups ?? [];
-  groups.value = overview.value.map((item) => item.group);
-  if (!groupId.value) {
+  const activeGroupId = groupId.value;
+  const result = await loadTaskTreeRoute(tasktreeAPI, activeGroupId);
+  if (result.view === "global") {
+    const overviewResponse = result.response;
+    if (!overviewResponse.ok || overviewResponse.data?.ok === false) {
+      loading.value = false;
+      error.value = overviewResponse.data?.error?.message || overviewResponse.error || "TaskTree 全局视图加载失败";
+      return;
+    }
+    overview.value = overviewResponse.data?.data?.groups ?? [];
+    groups.value = overview.value.map((item) => item.group);
     timeline.value = null;
     loading.value = false;
     await nextTick();
     positionTimelineAtNow("global");
     return;
   }
-  const timelineResponse = await tasktreeAPI.timeline(groupId.value);
+  const timelineResponse = result.response;
   loading.value = false;
   if (!timelineResponse.ok || timelineResponse.data?.ok === false || !timelineResponse.data?.data) {
     error.value = timelineResponse.data?.error?.message || timelineResponse.error || "TaskTree timeline 加载失败";
     return;
   }
   timeline.value = timelineResponse.data.data;
+  if (!groups.value.some((group) => group.id === timeline.value?.group.id)) {
+    groups.value = [...groups.value, timeline.value.group];
+  }
   initializedChildGroups.clear();
   syncSelectedTaskFromRoute();
   await nextTick();
-  positionTimelineAtNow(groupId.value);
+  positionTimelineAtNow(activeGroupId);
 }
 function selectGroup(event: Event) {
   const value = (event.target as HTMLSelectElement).value;