diff --git a/.github/workflows/unittest.yml b/.github/workflows/unittest.yml
index 1a2b093..8ca708b 100644
--- a/.github/workflows/unittest.yml
+++ b/.github/workflows/unittest.yml
@@ -18,7 +18,7 @@ jobs:
       max-parallel: 4
       matrix:
         python-version: [2.7, 3.6, 3.7, 3.8, 3.9]
-        os: [ubuntu-latest, windows-2019, macos-10.15]
+        os: [ubuntu-latest, windows-2019, macos-11]
 
     steps:
       - uses: actions/checkout@v2