diff --git a/mmcv/ops/chamfer_distance.py b/mmcv/ops/chamfer_distance.py
index d68eafb47c..1f908a5bbc 100644
--- a/mmcv/ops/chamfer_distance.py
+++ b/mmcv/ops/chamfer_distance.py
@@ -56,9 +56,11 @@ def forward(ctx, xyz1: Tensor, xyz2: Tensor) -> Sequence[Tensor]:
 
     @staticmethod
     @once_differentiable
-    def backward(ctx, grad_dist1: Tensor, grad_dist2: Tensor,
-                 grad_idx1: Tensor,
-                 grad_idx2: Tensor) -> Tuple[Tensor, Tensor]:
+    def backward(ctx,
+                 grad_dist1: Tensor,
+                 grad_dist2: Tensor,
+                 grad_idx1=None,
+                 grad_idx2=None) -> Tuple[Tensor, Tensor]:
         """
 
         Args:
@@ -66,10 +68,6 @@ def backward(ctx, grad_dist1: Tensor, grad_dist2: Tensor,
                 (xyz1 to xyz2) with shape (B, N).
             grad_dist2 (Tensor): Gradient of chamfer distance
                 (xyz2 to xyz1) with shape (B, N).
-            grad_idx1 (Tensor): Index of chamfer distance (xyz1 to xyz2)
-                with shape (B, N), which be used in compute gradient.
-            grad_idx2 (Tensor): Index of chamfer distance (xyz2 to xyz2)
-                with shape (B, N), which be used in compute gradient.
 
         Returns:
             Tuple[Tensor, Tensor]:
@@ -86,9 +84,9 @@ def backward(ctx, grad_dist1: Tensor, grad_dist2: Tensor,
         grad_xyz1 = torch.zeros(xyz1.size()).to(device)
         grad_xyz2 = torch.zeros(xyz2.size()).to(device)
 
-        ext_module.chamfer_distance_backward(xyz1, xyz2, grad_xyz1, grad_xyz2,
-                                             grad_dist1, grad_dist2, idx1,
-                                             idx2)
+        ext_module.chamfer_distance_backward(xyz1, xyz2, idx1, idx2,
+                                             grad_dist1, grad_dist2, grad_xyz1,
+                                             grad_xyz2)
         return grad_xyz1, grad_xyz2
 
 
diff --git a/mmcv/ops/csrc/parrots/chamfer_distance.cpp b/mmcv/ops/csrc/parrots/chamfer_distance.cpp
new file mode 100644
index 0000000000..dcff698931
--- /dev/null
+++ b/mmcv/ops/csrc/parrots/chamfer_distance.cpp
@@ -0,0 +1,35 @@
+// Copyright (c) OpenMMLab. All rights reserved.
+// Modified from
+// https://github.com/chrdiller/pyTorchChamferDistance/blob/master/chamfer_distance/chamfer_distance.cpp
+
+#include "pytorch_cpp_helper.hpp"
+#include "pytorch_device_registry.hpp"
+
+void chamfer_distance_forward_impl(const Tensor xyz1, const Tensor xyz2,
+                                   const Tensor dist1, const Tensor dist2,
+                                   const Tensor idx1, const Tensor idx2) {
+  DISPATCH_DEVICE_IMPL(chamfer_distance_forward_impl, xyz1, xyz2, dist1, dist2,
+                       idx1, idx2);
+}
+
+void chamfer_distance_backward_impl(const Tensor xyz1, const Tensor xyz2,
+                                    Tensor idx1, Tensor idx2, Tensor graddist1,
+                                    Tensor graddist2, Tensor gradxyz1,
+                                    Tensor gradxyz2) {
+  DISPATCH_DEVICE_IMPL(chamfer_distance_backward_impl, xyz1, xyz2, idx1, idx2,
+                       graddist1, graddist2, gradxyz1, gradxyz2);
+}
+
+void chamfer_distance_forward(const Tensor xyz1, const Tensor xyz2,
+                              const Tensor dist1, const Tensor dist2,
+                              const Tensor idx1, const Tensor idx2) {
+  chamfer_distance_forward_impl(xyz1, xyz2, dist1, dist2, idx1, idx2);
+}
+
+void chamfer_distance_backward(const Tensor xyz1, const Tensor xyz2,
+                               Tensor idx1, Tensor idx2, Tensor graddist1,
+                               Tensor graddist2, Tensor gradxyz1,
+                               Tensor gradxyz2) {
+  chamfer_distance_backward_impl(xyz1, xyz2, idx1, idx2, graddist1, graddist2,
+                                 gradxyz1, gradxyz2);
+}
diff --git a/mmcv/ops/csrc/parrots/chamfer_distance_parrots.cpp b/mmcv/ops/csrc/parrots/chamfer_distance_parrots.cpp
new file mode 100644
index 0000000000..db8eff1d6f
--- /dev/null
+++ b/mmcv/ops/csrc/parrots/chamfer_distance_parrots.cpp
@@ -0,0 +1,51 @@
+// Copyright (c) OpenMMLab. All rights reserved
+#include <parrots/compute/aten.hpp>
+#include <parrots/extension.hpp>
+#include <parrots/foundation/ssattrs.hpp>
+
+#include "chamfer_distance_pytorch.h"
+using namespace parrots;
+
+#ifdef MMCV_WITH_CUDA
+void chamfer_distance_forward_cuda_parrots(CudaContext& ctx,
+                                           const SSElement& attr,
+                                           const OperatorBase::in_list_t& ins,
+                                           OperatorBase::out_list_t& outs) {
+  auto xyz1 = buildATensor(ctx, ins[0]);
+  auto xyz2 = buildATensor(ctx, ins[1]);
+  auto dist1 = buildATensor(ctx, outs[0]);
+  auto dist2 = buildATensor(ctx, outs[1]);
+  auto idx1 = buildATensor(ctx, outs[2]);
+  auto idx2 = buildATensor(ctx, outs[3]);
+  chamfer_distance_forward(xyz1, xyz2, dist1, dist2, idx1, idx2);
+}
+
+void chamfer_distance_backward_cuda_parrots(CudaContext& ctx,
+                                            const SSElement& attr,
+                                            const OperatorBase::in_list_t& ins,
+                                            OperatorBase::out_list_t& outs) {
+  auto xyz1 = buildATensor(ctx, ins[0]);
+  auto xyz2 = buildATensor(ctx, ins[1]);
+  auto idx1 = buildATensor(ctx, ins[2]);
+  auto idx2 = buildATensor(ctx, ins[3]);
+  auto graddist1 = buildATensor(ctx, ins[4]);
+  auto graddist2 = buildATensor(ctx, ins[5]);
+  auto gradxyz1 = buildATensor(ctx, outs[0]);
+  auto gradxyz2 = buildATensor(ctx, outs[1]);
+  chamfer_distance_backward(xyz1, xyz2, idx1, idx2, graddist1, graddist2,
+                            gradxyz1, gradxyz2);
+}
+
+PARROTS_EXTENSION_REGISTER(chamfer_distance_forward)
+    .input(2)
+    .output(4)
+    .apply(chamfer_distance_forward_cuda_parrots)
+    .done();
+
+PARROTS_EXTENSION_REGISTER(chamfer_distance_backward)
+    .input(6)
+    .output(2)
+    .apply(chamfer_distance_backward_cuda_parrots)
+    .done();
+
+#endif
diff --git a/mmcv/ops/csrc/parrots/chamfer_distance_pytorch.h b/mmcv/ops/csrc/parrots/chamfer_distance_pytorch.h
new file mode 100644
index 0000000000..6405526b0c
--- /dev/null
+++ b/mmcv/ops/csrc/parrots/chamfer_distance_pytorch.h
@@ -0,0 +1,16 @@
+// Copyright (c) OpenMMLab. All rights reserved
+#ifndef ACTIVE_CHAMFER_DISTANCE_PYTORCH_H
+#define ACTIVE_CHAMFER_DISTANCE_PYTORCH_H
+#include <torch/extension.h>
+using namespace at;
+
+void chamfer_distance_forward(const Tensor xyz1, const Tensor xyz2,
+                              const Tensor dist1, const Tensor dist2,
+                              const Tensor idx1, const Tensor idx);
+
+void chamfer_distance_backward(const Tensor xyz1, const Tensor xyz2,
+                               Tensor idx1, Tensor idx2, Tensor graddist1,
+                               Tensor graddist2, Tensor gradxyz1,
+                               Tensor gradxyz2);
+
+#endif  // ACTIVE_CHAMFER_DISTANCE_PYTORCH_H
diff --git a/mmcv/ops/csrc/parrots/cudabind.cpp b/mmcv/ops/csrc/parrots/cudabind.cpp
index 04c6e36c4a..35c18da321 100644
--- a/mmcv/ops/csrc/parrots/cudabind.cpp
+++ b/mmcv/ops/csrc/parrots/cudabind.cpp
@@ -1589,3 +1589,40 @@ Tensor diff_iou_rotated_sort_vertices_forward_impl(Tensor vertices, Tensor mask,
 
 REGISTER_DEVICE_IMPL(diff_iou_rotated_sort_vertices_forward_impl, CUDA,
                      diff_iou_rotated_sort_vertices_forward_cuda);
+
+void ChamferDistanceForwardCUDAKernelLauncher(
+    const Tensor xyz1, const Tensor xyz2, const Tensor dist1,
+    const Tensor dist2, const Tensor idx1, const Tensor idx2);
+
+void ChamferDistanceBackwardCUDAKernelLauncher(
+    const Tensor xyz1, const Tensor xyz2, Tensor idx1, Tensor idx2,
+    Tensor grad_dist1, Tensor grad_dist2, Tensor grad_xyz1, Tensor grad_xyz2);
+
+void chamfer_distance_forward_cuda(const Tensor xyz1, const Tensor xyz2,
+                                   const Tensor dist1, const Tensor dist2,
+                                   const Tensor idx1, const Tensor idx2) {
+  ChamferDistanceForwardCUDAKernelLauncher(xyz1, xyz2, dist1, dist2, idx1,
+                                           idx2);
+};
+
+void chamfer_distance_backward_cuda(const Tensor xyz1, const Tensor xyz2,
+                                    Tensor idx1, Tensor idx2, Tensor graddist1,
+                                    Tensor graddist2, Tensor gradxyz1,
+                                    Tensor gradxyz2) {
+  ChamferDistanceBackwardCUDAKernelLauncher(xyz1, xyz2, idx1, idx2, graddist1,
+                                            graddist2, gradxyz1, gradxyz2);
+};
+
+void chamfer_distance_forward_impl(const Tensor xyz1, const Tensor xyz2,
+                                   const Tensor dist1, const Tensor dist2,
+                                   const Tensor idx1, const Tensor idx2);
+
+void chamfer_distance_backward_impl(const Tensor xyz1, const Tensor xyz2,
+                                    Tensor idx1, Tensor idx2, Tensor graddist1,
+                                    Tensor graddist2, Tensor gradxyz1,
+                                    Tensor gradxyz2);
+
+REGISTER_DEVICE_IMPL(chamfer_distance_forward_impl, CUDA,
+                     chamfer_distance_forward_cuda);
+REGISTER_DEVICE_IMPL(chamfer_distance_backward_impl, CUDA,
+                     chamfer_distance_backward_cuda);
diff --git a/mmcv/ops/csrc/pytorch/chamfer_distance.cpp b/mmcv/ops/csrc/pytorch/chamfer_distance.cpp
index 6ea1ba675e..dcff698931 100644
--- a/mmcv/ops/csrc/pytorch/chamfer_distance.cpp
+++ b/mmcv/ops/csrc/pytorch/chamfer_distance.cpp
@@ -13,11 +13,11 @@ void chamfer_distance_forward_impl(const Tensor xyz1, const Tensor xyz2,
 }
 
 void chamfer_distance_backward_impl(const Tensor xyz1, const Tensor xyz2,
-                                    Tensor gradxyz1, Tensor gradxyz2,
-                                    Tensor graddist1, Tensor graddist2,
-                                    Tensor idx1, Tensor idx2) {
-  DISPATCH_DEVICE_IMPL(chamfer_distance_backward_impl, xyz1, xyz2, gradxyz1,
-                       gradxyz2, graddist1, graddist2, idx1, idx2);
+                                    Tensor idx1, Tensor idx2, Tensor graddist1,
+                                    Tensor graddist2, Tensor gradxyz1,
+                                    Tensor gradxyz2) {
+  DISPATCH_DEVICE_IMPL(chamfer_distance_backward_impl, xyz1, xyz2, idx1, idx2,
+                       graddist1, graddist2, gradxyz1, gradxyz2);
 }
 
 void chamfer_distance_forward(const Tensor xyz1, const Tensor xyz2,
@@ -27,9 +27,9 @@ void chamfer_distance_forward(const Tensor xyz1, const Tensor xyz2,
 }
 
 void chamfer_distance_backward(const Tensor xyz1, const Tensor xyz2,
-                               Tensor gradxyz1, Tensor gradxyz2,
-                               Tensor graddist1, Tensor graddist2, Tensor idx1,
-                               Tensor idx2) {
-  chamfer_distance_backward_impl(xyz1, xyz2, gradxyz1, gradxyz2, graddist1,
-                                 graddist2, idx1, idx2);
+                               Tensor idx1, Tensor idx2, Tensor graddist1,
+                               Tensor graddist2, Tensor gradxyz1,
+                               Tensor gradxyz2) {
+  chamfer_distance_backward_impl(xyz1, xyz2, idx1, idx2, graddist1, graddist2,
+                                 gradxyz1, gradxyz2);
 }
diff --git a/mmcv/ops/csrc/pytorch/cuda/chamfer_distance_cuda.cu b/mmcv/ops/csrc/pytorch/cuda/chamfer_distance_cuda.cu
index 980482eb54..6effa29ee7 100644
--- a/mmcv/ops/csrc/pytorch/cuda/chamfer_distance_cuda.cu
+++ b/mmcv/ops/csrc/pytorch/cuda/chamfer_distance_cuda.cu
@@ -33,8 +33,8 @@ void ChamferDistanceForwardCUDAKernelLauncher(
 }
 
 void ChamferDistanceBackwardCUDAKernelLauncher(
-    const Tensor xyz1, const Tensor xyz2, Tensor grad_xyz1, Tensor grad_xyz2,
-    Tensor grad_dist1, Tensor grad_dist2, Tensor idx1, Tensor idx2) {
+    const Tensor xyz1, const Tensor xyz2, Tensor idx1, Tensor idx2,
+    Tensor grad_dist1, Tensor grad_dist2, Tensor grad_xyz1, Tensor grad_xyz2) {
   int batch_size = xyz1.size(0);
   int n = xyz1.size(1);
   int m = xyz2.size(1);
diff --git a/mmcv/ops/csrc/pytorch/cuda/cudabind.cpp b/mmcv/ops/csrc/pytorch/cuda/cudabind.cpp
index 12cf7afdc2..1df35f510d 100644
--- a/mmcv/ops/csrc/pytorch/cuda/cudabind.cpp
+++ b/mmcv/ops/csrc/pytorch/cuda/cudabind.cpp
@@ -1706,8 +1706,8 @@ void ChamferDistanceForwardCUDAKernelLauncher(
     const Tensor dist2, const Tensor idx1, const Tensor idx2);
 
 void ChamferDistanceBackwardCUDAKernelLauncher(
-    const Tensor xyz1, const Tensor xyz2, Tensor grad_xyz1, Tensor grad_xyz2,
-    Tensor grad_dist1, Tensor grad_dist2, Tensor idx1, Tensor idx2);
+    const Tensor xyz1, const Tensor xyz2, Tensor idx1, Tensor idx2,
+    Tensor grad_dist1, Tensor grad_dist2, Tensor grad_xyz1, Tensor grad_xyz2);
 
 void chamfer_distance_forward_cuda(const Tensor xyz1, const Tensor xyz2,
                                    const Tensor dist1, const Tensor dist2,
@@ -1717,11 +1717,11 @@ void chamfer_distance_forward_cuda(const Tensor xyz1, const Tensor xyz2,
 };
 
 void chamfer_distance_backward_cuda(const Tensor xyz1, const Tensor xyz2,
-                                    Tensor gradxyz1, Tensor gradxyz2,
-                                    Tensor graddist1, Tensor graddist2,
-                                    Tensor idx1, Tensor idx2) {
-  ChamferDistanceBackwardCUDAKernelLauncher(xyz1, xyz2, gradxyz1, gradxyz2,
-                                            graddist1, graddist2, idx1, idx2);
+                                    Tensor idx1, Tensor idx2, Tensor graddist1,
+                                    Tensor graddist2, Tensor gradxyz1,
+                                    Tensor gradxyz2) {
+  ChamferDistanceBackwardCUDAKernelLauncher(xyz1, xyz2, idx1, idx2, graddist1,
+                                            graddist2, gradxyz1, gradxyz2);
 };
 
 void chamfer_distance_forward_impl(const Tensor xyz1, const Tensor xyz2,
@@ -1729,9 +1729,9 @@ void chamfer_distance_forward_impl(const Tensor xyz1, const Tensor xyz2,
                                    const Tensor idx1, const Tensor idx2);
 
 void chamfer_distance_backward_impl(const Tensor xyz1, const Tensor xyz2,
-                                    Tensor gradxyz1, Tensor gradxyz2,
-                                    Tensor graddist1, Tensor graddist2,
-                                    Tensor idx1, Tensor idx2);
+                                    Tensor idx1, Tensor idx2, Tensor graddist1,
+                                    Tensor graddist2, Tensor gradxyz1,
+                                    Tensor gradxyz2);
 
 REGISTER_DEVICE_IMPL(chamfer_distance_forward_impl, CUDA,
                      chamfer_distance_forward_cuda);
diff --git a/mmcv/ops/csrc/pytorch/pybind.cpp b/mmcv/ops/csrc/pytorch/pybind.cpp
index c134090871..6fb7a8a53f 100644
--- a/mmcv/ops/csrc/pytorch/pybind.cpp
+++ b/mmcv/ops/csrc/pytorch/pybind.cpp
@@ -419,9 +419,9 @@ void chamfer_distance_forward(const Tensor xyz1, const Tensor xyz2,
                               const Tensor idx1, const Tensor idx);
 
 void chamfer_distance_backward(const Tensor xyz1, const Tensor xyz2,
-                               Tensor gradxyz1, Tensor gradxyz2,
-                               Tensor graddist1, Tensor graddist2, Tensor idx1,
-                               Tensor idx2);
+                               Tensor idx1, Tensor idx2, Tensor graddist1,
+                               Tensor graddist2, Tensor gradxyz1,
+                               Tensor gradxyz2);
 
 PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
   m.def("upfirdn2d", &upfirdn2d, "upfirdn2d (CUDA)", py::arg("input"),
@@ -838,8 +838,8 @@ PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
         py::arg("dist1"), py::arg("dist2"), py::arg("idx1"), py::arg("idx2"));
   m.def("chamfer_distance_backward", &chamfer_distance_backward,
         "chamfer_distance_backward", py::arg("xyz1"), py::arg("xyz2"),
-        py::arg("gradxyz1"), py::arg("gradxyz2"), py::arg("graddist1"),
-        py::arg("graddist2"), py::arg("idx1"), py::arg("idx2"));
+        py::arg("idx1"), py::arg("idx2"), py::arg("graddist1"),
+        py::arg("graddist2"), py::arg("gradxyz1"), py::arg("gradxyz2"));
   m.def("prroi_pool_forward", &prroi_pool_forward, "prroi_pool forward",
         py::arg("input"), py::arg("rois"), py::arg("output"),
         py::arg("pooled_height"), py::arg("pooled_width"),