diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index fa40e3e73..350186d9f 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -23,7 +23,7 @@ jobs:
     - name: Install rdkit
       run: conda create -c conda-forge -n my-rdkit-env python=${{ matrix.python-version }} rdkit openbabel;
     - name: Install dependencies
-      run: source $CONDA/bin/activate my-rdkit-env && pip install .[amber] coverage codecov
+      run: source $CONDA/bin/activate my-rdkit-env && pip install .[amber,ase,pymatgen] coverage codecov
     - name: Test
       run: source $CONDA/bin/activate my-rdkit-env && cd tests && coverage run --source=../dpdata -m unittest && cd .. && coverage combine tests/.coverage && coverage report
     - name: Run codecov
diff --git a/dpdata/plugins/pymatgen.py b/dpdata/plugins/pymatgen.py
index a047249e1..84d71f0e4 100644
--- a/dpdata/plugins/pymatgen.py
+++ b/dpdata/plugins/pymatgen.py
@@ -8,7 +8,7 @@ def to_system(self, data, **kwargs):
         """
         structures = []
         try:
-            from pymatgen import Structure
+            from pymatgen.core import Structure
         except ModuleNotFoundError as e:
             raise ImportError('No module pymatgen.Structure') from e
 
diff --git a/setup.py b/setup.py
index 8fb19676c..59133b924 100644
--- a/setup.py
+++ b/setup.py
@@ -52,6 +52,7 @@
     extras_require={
         'ase': ['ase'],
         'amber': ['parmed'],
+        'pymatgen': ['pymatgen'],
     }
 )