diff --git a/dpgen/auto_test/Gamma.py b/dpgen/auto_test/Gamma.py
index 4ea93693e..6bce02380 100644
--- a/dpgen/auto_test/Gamma.py
+++ b/dpgen/auto_test/Gamma.py
@@ -369,7 +369,7 @@ def __poscar_fix(self, poscar) -> None:
 
     def __stru_fix(self, stru) -> None:
         fix_dict = {"true": True, "false": False}
-        fix_xyz = [fix_dict[i] for i in self.addfix]
+        fix_xyz = [fix_dict[i] for i in self.add_fix]
         abacus.stru_fix_atom(stru, fix_atom=fix_xyz)
 
     def __inLammpes_fix(self, inLammps) -> None: