diff --git a/deepmd/entrypoints/freeze.py b/deepmd/entrypoints/freeze.py
index 8b0acf0e98..172c765646 100755
--- a/deepmd/entrypoints/freeze.py
+++ b/deepmd/entrypoints/freeze.py
@@ -7,6 +7,7 @@
 """
 
 import logging
+import google.protobuf.message
 from deepmd.env import tf, FITTING_NET_PATTERN
 from deepmd.utils.sess import run_sess
 from deepmd.utils.graph import get_pattern_nodes_from_graph_def