diff --git a/nni/compression/pytorch/speedup/v2/model_speedup.py b/nni/compression/pytorch/speedup/v2/model_speedup.py
index 49a4bae3e..368329b3c 100644
--- a/nni/compression/pytorch/speedup/v2/model_speedup.py
+++ b/nni/compression/pytorch/speedup/v2/model_speedup.py
@@ -32,6 +32,13 @@ from .replacer import Replacer, DefaultReplacer
 from .utils import tree_map_zip
 
 
+def _normalize_input(dummy_input: Any) -> Any:
+    if isinstance(dummy_input, torch.Tensor):
+        dummy_input = (dummy_input, )
+    elif isinstance(dummy_input, list):
+        dummy_input = tuple(dummy_input)
+    return dummy_input
+
 @compatibility(is_backward_compatible=True)
 class ModelSpeedup(torch.fx.Interpreter):
     """
@@ -88,7 +95,7 @@ class ModelSpeedup(torch.fx.Interpreter):
                  graph_module: GraphModule | None = None,
                  garbage_collect_values: bool = True,
                  logger: logging.Logger | None = None):
-        self.dummy_input = (dummy_input,) if isinstance(dummy_input, torch.Tensor) else tuple(dummy_input)
+        self.dummy_input = _normalize_input(dummy_input)
         self.bound_model = model
         self.graph_module = graph_module if isinstance(graph_module, GraphModule) else concrete_trace(model, self.dummy_input)