diff --git a/src/workflow.py b/src/workflow.py
index 94cd6f9..e6a05d4 100644
--- a/src/workflow.py
+++ b/src/workflow.py
@@ -47,52 +47,58 @@ class Workflow:
                 # ==========================
                 # Step: 00.md
                 # ==========================
-                # --- 第一轮初始化：POSCAR -> model.xyz ---
-                if iter_id == 0:
-                    os.makedirs(step_dir, exist_ok=True)
+                if step_name == "00.md":
+                    # 1. 【修正点】先定义 step_dir，确保后续都能访问到
+                    step_dir = os.path.join(iter_path, "00.md")
 
-                    # 1. 获取文件名和路径
-                    poscar_name = self.param['files']['poscar']
-                    poscar_src = os.path.join(self.data_dir, poscar_name)
+                    # --- 第一轮初始化：POSCAR -> model.xyz ---
+                    if iter_id == 0:
+                        # 2. 现在使用 step_dir 是安全的
+                        os.makedirs(step_dir, exist_ok=True)
 
-                    # 2. 复制原始 POSCAR 到 step_dir
-                    if not os.path.exists(poscar_src):
-                        self.logger.error(f"Initial POSCAR not found: {poscar_src}")
-                        return  # 或者抛出异常
-                    shutil.copy(poscar_src, os.path.join(step_dir, poscar_name))
+                        # 获取文件名和路径
+                        poscar_name = self.param['files']['poscar']
+                        poscar_src = os.path.join(self.data_dir, poscar_name)
 
-                    # 3. 获取原子标签 Label
-                    # 假设 config/param.yaml 里是: label: "Li Ge P S"
-                    atom_labels = self.param['files'].get('label', '')
-                    if not atom_labels:
-                        self.logger.error("Missing 'label' in param.yaml files section.")
-                        return
+                        # 复制原始 POSCAR
+                        if not os.path.exists(poscar_src):
+                            self.logger.error(f"Initial POSCAR not found: {poscar_src}")
+                            return
+                        shutil.copy(poscar_src, os.path.join(step_dir, poscar_name))
 
-                    # 4. 构建 gpumdkit 命令
-                    # 命令格式: gpumdkit.sh -addlabel filename Li Ge P S
-                    # 注意：这里我们假设 machine.yaml 里定义了一个叫 'gpumdkit' 的 executor
-                    # 或者我们直接构建 shell 命令，因为这通常是一个轻量级操作
+                        # 获取标签
+                        atom_labels = self.param['files'].get('label', '')
+                        if not atom_labels:
+                            self.logger.error("Missing 'label' in param.yaml files section.")
+                            return
 
-                    # 方法 A: 如果 machine.yaml 里配置了 gpumdkit 的路径
-                    kit_path = self.machine.config['paths'].get('gpumdkit', 'gpumdkit.sh')
-                    cmd = f"{kit_path} -addlabel {poscar_name} {atom_labels}"
+                        # 执行转换
+                        kit_path = self.machine.config['paths'].get('gpumdkit', 'gpumdkit.sh')
+                        # 确保使用绝对路径，防止 subprocess 找不到
+                        if not os.path.isabs(kit_path):
+                            # 假设相对于项目根目录，或者在 PATH 中
+                            pass
 
-                    self.logger.info(f"Initializing model.xyz with command: {cmd}")
+                        cmd = f"{kit_path} -addlabel {poscar_name} {atom_labels}"
 
-                    # 执行转化
-                    try:
-                        # 必须在 step_dir 下执行，以便生成 model.xyz 在当前目录
-                        subprocess.check_call(cmd, shell=True, cwd=step_dir)
-                    except subprocess.CalledProcessError as e:
-                        self.logger.error(f"Failed to convert POSCAR to model.xyz: {e}")
-                        return
+                        self.logger.info(f"Initializing model.xyz with command: {cmd}")
+                        try:
+                            subprocess.check_call(cmd, shell=True, cwd=step_dir)
+                        except subprocess.CalledProcessError as e:
+                            self.logger.error(f"Failed to convert POSCAR: {e}")
+                            return
 
-                    # 检查生成结果
-                    if not os.path.exists(os.path.join(step_dir, "model.xyz")):
-                        self.logger.error("model.xyz was not generated. Check gpumdkit.sh.")
-                        return
-                    else:
-                        self.logger.info("Successfully generated model.xyz")
+                        if not os.path.exists(os.path.join(step_dir, "model.xyz")):
+                            self.logger.error("model.xyz was not generated.")
+                            return
+                        else:
+                            self.logger.info("Successfully generated model.xyz")
+
+                    # --- 遍历子任务 (preheat, production...) ---
+                    for sub in step_conf.get('sub_tasks', []):
+                        template_sub_name = sub['template_sub']
+                        sub_work_dir = os.path.join(step_dir, template_sub_name)
+                        template_path = os.path.join(self.template_dir, "00.md", template_sub_name)
 
                 # ==========================
                 # Step: 01.select