diff --git a/deepmd/dpmodel/model/__init__.py b/deepmd/dpmodel/model/__init__.py
index cb796e6d35..c1ff15ab0d 100644
--- a/deepmd/dpmodel/model/__init__.py
+++ b/deepmd/dpmodel/model/__init__.py
@@ -8,6 +8,8 @@
 according to output variable definition
 `deepmd.dpmodel.OutputVariableDef`.
 
+All models should be inherited from :class:`deepmd.dpmodel.model.base_model.BaseModel`.
+Models generated by `make_model` have already done it.
 """
 
 from .dp_model import (
diff --git a/deepmd/pt/model/model/__init__.py b/deepmd/pt/model/model/__init__.py
index 3ba7772c06..3098dc7677 100644
--- a/deepmd/pt/model/model/__init__.py
+++ b/deepmd/pt/model/model/__init__.py
@@ -7,6 +7,8 @@
 communication of the atomic properties according to output variable
 definition `deepmd.dpmodel.OutputVariableDef`.
 
+All models should be inherited from :class:`deepmd.pt.model.model.model.BaseModel`.
+Models generated by `make_model` have already done it.
 """
 
 import copy