diff --git a/deepmd/driver.py b/deepmd/driver.py
index 0b48f2ac84..998edcbc18 100644
--- a/deepmd/driver.py
+++ b/deepmd/driver.py
@@ -62,7 +62,8 @@ def label(self, data: dict) -> dict:
         atype = sorted_data["atom_types"]
 
         coord = data["coords"].reshape((nframes, natoms * 3))
-        if "nopbc" not in data:
+        # sometimes data["nopbc"] may be False
+        if not data.get("nopbc", False):
             cell = data["cells"].reshape((nframes, 9))
         else:
             cell = None