diff --git a/deepmd/infer/deep_eval.py b/deepmd/infer/deep_eval.py
index 8c7d6d5295..be7ac20e39 100644
--- a/deepmd/infer/deep_eval.py
+++ b/deepmd/infer/deep_eval.py
@@ -441,7 +441,7 @@ def _standard_input(self, coords, cells, atom_types, fparam, aparam, mixed_type)
         coords = np.array(coords)
         if cells is not None:
             cells = np.array(cells)
-        atom_types = np.array(atom_types)
+        atom_types = np.array(atom_types, dtype=np.int32)
         if fparam is not None:
             fparam = np.array(fparam)
         if aparam is not None: