diff --git a/sot/opcode_translator/executor/opcode_executor.py b/sot/opcode_translator/executor/opcode_executor.py
index 45aeeec0b..ca60f7563 100644
--- a/sot/opcode_translator/executor/opcode_executor.py
+++ b/sot/opcode_translator/executor/opcode_executor.py
@@ -2071,8 +2071,10 @@ def _break_graph_in_for_loop(
             self._graph.pycode_gen.gen_store(ret_names[idx], self._code)
 
         # 3. setup vars which is created in loop
+        undefined_names = set()
         for name in loop_body_inputs[:-1]:
             if not self.has_var(name, all_used_vars[name]):
+                undefined_names.add(name)
                 self._graph.pycode_gen.gen_load_const(SotUndefinedVar())
                 self._graph.pycode_gen.gen_store(name, self._code)
 
@@ -2137,6 +2139,10 @@ def _break_graph_in_for_loop(
         for stack_arg in self.stack:
             var_loader.load(stack_arg)
         for name in fn_inputs:
+            if not self.has_var(name) and name not in undefined_names:
+                undefined_names.add(name)
+                self._graph.pycode_gen.gen_load_const(SotUndefinedVar())
+                self._graph.pycode_gen.gen_store(name, self._code)
             self._graph.pycode_gen.gen_load(name)
 
         self._graph.pycode_gen.gen_call_function(
diff --git a/sot/translate.py b/sot/translate.py
index 83719aaa3..7a342e659 100644
--- a/sot/translate.py
+++ b/sot/translate.py
@@ -81,8 +81,7 @@ def callback(frame):
     def impl_sot(*args: P.args, **kwargs: P.kwargs) -> R:
         assert hasattr(
             fn, "__code__"
-        ), "Target function has not code for simulating."
-
+        ), "Target function doesn't have code for simulating."
         StepInfoManager().sot_step()
         GraphLogger().clear()
         paddle.framework.core.set_eval_frame(callback)
diff --git a/tests/test_12_for_loop.py b/tests/test_12_for_loop.py
index 4a90adcb7..710af8476 100644
--- a/tests/test_12_for_loop.py
+++ b/tests/test_12_for_loop.py
@@ -248,6 +248,37 @@ def test_run(self):
         self.assert_nest_match(InstructionTranslatorCache().translate_count, 1)
 
 
+# after_loop_fn need zzz, and zzz is created as UndefinedVar when generating loop body
+# do not set zzz as UndefinedVar again
+def undefined_var_case_0():
+    for i in [1, 2]:
+        sot.psdb.breakgraph()
+        zzz = i
+
+    zzz = zzz + 1
+    return zzz
+
+
+# after_loop_fn need create zzz as UndefinedVar
+def undefined_var_case_1():
+    for i in [1, 2]:
+        sot.psdb.breakgraph()
+        aaa = i
+
+    for i in [1, 3]:
+        zzz = i
+    zzz = zzz + 1
+    return zzz
+
+
+class TestUndefinedVarInRiskyCodes(TestCaseBase):
+    def test_undefined_var_case_0(self):
+        self.assert_results(undefined_var_case_0)
+
+    def test_undefined_var_case_1(self):
+        self.assert_results(undefined_var_case_1)
+
+
 if __name__ == "__main__":
     with strict_mode_guard(0):
         unittest.main()