diff --git a/docs/readthedocs/source/doc/PythonAPI/Orca/orca.rst b/docs/readthedocs/source/doc/PythonAPI/Orca/orca.rst
index f52a5d8a..5e038f8b 100644
--- a/docs/readthedocs/source/doc/PythonAPI/Orca/orca.rst
+++ b/docs/readthedocs/source/doc/PythonAPI/Orca/orca.rst
@@ -35,6 +35,29 @@ orca.learn.pytorch.estimator
     :undoc-members:
     :show-inheritance:
 
+
+orca.learn.pytorch.pytorch_ray_estimator
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Orca Pytorch Estimator with backend of "horovod" or "torch_distributed".
+
+.. autoclass:: bigdl.orca.learn.pytorch.pytorch_ray_estimator.PyTorchRayEstimator
+    :members:
+    :undoc-members:
+    :show-inheritance:
+
+
+orca.learn.pytorch.pytorch_spark_estimator
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Orca Pytorch Estimator with backend of "bigdl".
+
+.. autoclass:: bigdl.orca.learn.pytorch.pytorch_spark_estimator.PyTorchSparkEstimator
+    :members:
+    :undoc-members:
+    :show-inheritance:
+
+
 orca.learn.openvino.estimator
 ------------------------------