diff --git a/src/workflow.py b/src/workflow.py
index d14ed83..dc4e587 100644
--- a/src/workflow.py
+++ b/src/workflow.py
@@ -78,7 +78,12 @@ class Workflow:
                             self.logger.info("Skipping Init (Already Done).")
                     else:
                         # --- [新增逻辑] 后续轮次：从上一轮复制 model.xyz ---
-                        # 只要当前目录下没有 model.xyz，就去搬运
+
+                        # 1. 【核心修复】必须先确保目标文件夹存在！
+                        if not os.path.exists(step_dir):
+                            os.makedirs(step_dir, exist_ok=True)
+
+                        # 2. 检查当前目录是否已有 model.xyz
                         if not os.path.exists(os.path.join(step_dir, "model.xyz")):
                             prev_iter_name = f"iter_{iter_id - 1:02d}"
                             prev_model_src = os.path.join(self.workspace, prev_iter_name, "00.md", "model.xyz")