diff --git a/src/workflow.py b/src/workflow.py
index 37db84b..4236de9 100644
--- a/src/workflow.py
+++ b/src/workflow.py
@@ -408,7 +408,7 @@ class Workflow:
 
                         # === 分支 B: 随机筛选 (保持不变) ===
                         elif method == "random":
-                            min_n, max_n = params[1], params[2]
+                            min_n, max_n = params[0], params[1]
                             input_str = f"203\ndump.xyz train.xyz nep.txt\n2\n{min_n} {max_n}"
                             self.logger.info(f"Random selection: {min_n}-{max_n}")
                             if run_cmd_with_log(kit_path, step_dir, "select_exec.log", input_str=input_str):