diff --git a/scripts/start_all.py b/scripts/start_all.py
index 9eb7d3a..1a1e7a0 100644
--- a/scripts/start_all.py
+++ b/scripts/start_all.py
@@ -112,7 +112,7 @@ def main() -> None:
         stopped = stop_ports((2024, 3000))
         if stopped:
             print(f"已清理残留服务进程：{stopped}")
-        sys.exit(0)
+    sys.exit(0)
 
 
 if __name__ == "__main__":
diff --git a/tests/unit/test_start_all.py b/tests/unit/test_start_all.py
new file mode 100644
index 0000000..4e56088
--- /dev/null
+++ b/tests/unit/test_start_all.py
@@ -0,0 +1,57 @@
+from __future__ import annotations
+
+from unittest.mock import Mock
+
+import pytest
+
+from scripts import start_all
+
+
+@pytest.fixture
+def services(monkeypatch: pytest.MonkeyPatch) -> tuple[Mock, Mock, Mock]:
+    backend, frontend = Mock(), Mock()
+    backend.poll.return_value = None
+    frontend.poll.return_value = None
+    processes = iter((backend, frontend))
+    monkeypatch.setattr(start_all, "start_process", lambda *args, **kwargs: next(processes))
+    stop_ports = Mock(return_value=[])
+    monkeypatch.setattr(start_all, "stop_ports", stop_ports)
+    # Interrupt the monitoring loop instead of sleeping or starting real services.
+    monkeypatch.setattr(start_all.time, "sleep", Mock(side_effect=KeyboardInterrupt))
+    return backend, frontend, stop_ports
+
+
+@pytest.mark.parametrize("failed_service,return_code", [("backend", 1), ("frontend", 2)])
+def test_service_failure_preserves_error_after_cleanup(
+    services: tuple[Mock, Mock, Mock], failed_service: str, return_code: int
+) -> None:
+    backend, frontend, stop_ports = services
+    failed, remaining = (backend, frontend) if failed_service == "backend" else (frontend, backend)
+    failed.poll.return_value = return_code
+
+    with pytest.raises(SystemExit) as raised:
+        start_all.main()
+
+    # A SystemExit message produces status 1 and identifies the failed service.
+    assert raised.value.code == f"{failed_service} exited: {return_code}"
+    failed.terminate.assert_not_called()
+    remaining.terminate.assert_called_once_with()
+    backend.wait.assert_called_once_with(timeout=5)
+    frontend.wait.assert_called_once_with(timeout=5)
+    stop_ports.assert_called_once_with((2024, 3000))
+
+
+def test_keyboard_interrupt_still_stops_services_successfully(
+    services: tuple[Mock, Mock, Mock], capsys: pytest.CaptureFixture[str]
+) -> None:
+    backend, frontend, stop_ports = services
+
+    with pytest.raises(SystemExit) as raised:
+        start_all.main()
+
+    assert raised.value.code == 0
+    assert "正在停止服务..." in capsys.readouterr().out
+    for process in (backend, frontend):
+        process.terminate.assert_called_once_with()
+        process.wait.assert_called_once_with(timeout=5)
+    stop_ports.assert_called_once_with((2024, 3000))