diff --git a/.github/workflows/py.yml b/.github/workflows/py.yml
index 95839d51e..a94de2947 100644
--- a/.github/workflows/py.yml
+++ b/.github/workflows/py.yml
@@ -23,7 +23,7 @@ jobs:
       - name: Set up Python 3.6
         uses: actions/setup-python@v2
         with:
-          python-version: 3.6
+          python-version: '3.6'
 
       - name: Install dependencies
         # flake8-bugbear flake8-comprehensions are useful but not available internally
@@ -52,18 +52,13 @@ jobs:
     steps:
       - uses: actions/checkout@v2
 
-      - name: Set up Python 3.9
-        uses: actions/setup-python@v2
-        with:
-          python-version: 3.9
-
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          python -m pip install --pre oneflow -f https://staging.oneflow.info/branch/master/cpu
+          python -m pip install --pre oneflow -f https://oneflow-staging.oss-cn-beijing.aliyuncs.com/branch/master/cpu
           python -m pip install pybind11
           python -m pip install torch torchvision torchaudio
-      
+
       - name: Build and install
         run: |
           python -m pip install -e .
diff --git a/setup.py b/setup.py
index 5874efab7..7d4a8f7d0 100644
--- a/setup.py
+++ b/setup.py
@@ -46,8 +46,12 @@ def write_version_file():
 
 
 def get_pybind11():
-    import pybind11 as pb
-
+    try:
+        import pybind11 as pb
+    except ImportError:
+        print("pybind11 not found, installing...")
+        os.system(f"{sys.executable} -m pip install pybind11")
+        import pybind11 as pb
     return pb