diff --git a/dpdata/plugins/deepmd.py b/dpdata/plugins/deepmd.py
index d8ed0aed..1ed79f72 100644
--- a/dpdata/plugins/deepmd.py
+++ b/dpdata/plugins/deepmd.py
@@ -302,6 +302,8 @@ def to_system(
         **kwargs : dict
             other parameters
         """
+        import h5py
+
         if isinstance(file_name, (h5py.Group, h5py.File)):
             dpdata.deepmd.hdf5.dump(
                 file_name, "", data, set_size=set_size, comp_prec=comp_prec
@@ -332,6 +334,8 @@ def from_multi_systems(self, directory: str, **kwargs) -> h5py.Group:
         h5py.Group
             a HDF5 group in the HDF5 file
         """
+        import h5py
+
         with h5py.File(directory, "r") as f:
             for ff in f.keys():
                 yield f[ff]
@@ -355,6 +359,8 @@ def to_multi_systems(
         h5py.Group
             a HDF5 group with the name of formula
         """
+        import h5py
+
         with h5py.File(directory, "w") as f:
             for ff in formulas:
                 yield f.create_group(ff)