diff --git a/.gitea/workflows/build.yaml b/.gitea/workflows/build.yaml
index 108f4d2..5674c79 100755
--- a/.gitea/workflows/build.yaml
+++ b/.gitea/workflows/build.yaml
@@ -23,6 +23,8 @@ jobs:
           apt-get install lftp -y          
       - name: Checkout
         uses: https://git.hmtsai.cn/actions/checkout@v4
+      - name: Download submodule
+        run: git submodule update --init --recursive
       - name: Cache mdbook
         uses: https://git.hmtsai.cn/actions/cache@v4
         id: cache-mdbook