diff --git a/pipeline_service/init.py b/pipeline_service/init.py
index 62f25a7..cc897ab 100644
--- a/pipeline_service/init.py
+++ b/pipeline_service/init.py
@@ -393,6 +393,10 @@ async def shell_exec(command: str, workdir: str = None, timeout: int = 60):
     """
     cwd = workdir or _resolve_workdir()
     cwd = os.path.abspath(cwd)
+    # 如果指定目录不存在，回落到可写基础目录
+    if not os.path.isdir(cwd):
+        cwd = _resolve_workdir()
+        cwd = os.path.abspath(cwd)
     base = os.path.abspath(_SHELL_BASE_DIR)
     fallback = os.path.abspath(_WORKDIR_FALLBACK)
     if not (cwd.startswith(base) or cwd.startswith(fallback)):