diff --git a/mmcv/onnx/info.py b/mmcv/onnx/info.py
index 060efafe2..e59997368 100644
--- a/mmcv/onnx/info.py
+++ b/mmcv/onnx/info.py
@@ -1,6 +1,8 @@
 # Copyright (c) OpenMMLab. All rights reserved.
 import os
 
+import torch
+
 
 def is_custom_op_loaded():
     flag = False
@@ -16,4 +18,4 @@ def is_custom_op_loaded():
             flag = os.path.exists(ort_lib_path)
         except (ImportError, ModuleNotFoundError):
             pass
-    return flag
+    return flag or torch.__version__ == 'parrots'
diff --git a/mmcv/ops/csrc/parrots/sync_bn_parrots.cpp b/mmcv/ops/csrc/parrots/sync_bn_parrots.cpp
index 6130c3ff5..0b1855abd 100644
--- a/mmcv/ops/csrc/parrots/sync_bn_parrots.cpp
+++ b/mmcv/ops/csrc/parrots/sync_bn_parrots.cpp
@@ -45,7 +45,7 @@ void sync_bn_forward_output_cuda_parrots(CudaContext& ctx,
   auto running_var = buildATensor(ctx, outs[1]);
   auto norm = buildATensor(ctx, outs[2]);
   auto std = buildATensor(ctx, outs[3]);
-  auto output = buildATensor(ctx, outs[3]);
+  auto output = buildATensor(ctx, outs[4]);
   sync_bn_forward_output_cuda(input, mean, var, running_mean, running_var,
                               weight, bias, norm, std, output, eps, momentum,
                               group_size);