diff --git a/doc/install/install-from-source.md b/doc/install/install-from-source.md
index 404f3ab114..9b2cf27be2 100644
--- a/doc/install/install-from-source.md
+++ b/doc/install/install-from-source.md
@@ -120,6 +120,7 @@ Note that TensorFlow may have specific requirements for the compiler version to
 
 :::{tab-item} PyTorch {{ pytorch_icon }}
 
+You can set the environment variable `export DP_ENABLE_PYTORCH=1` to enable customized C++ OPs in the PyTorch backend.
 Note that PyTorch may have specific requirements for the compiler version to support the C++ standard version and [`_GLIBCXX_USE_CXX11_ABI`](https://gcc.gnu.org/onlinedocs/libstdc++/manual/using_dual_abi.html) used by PyTorch.
 
 :::