diff --git a/docs/useful_tools.md b/docs/useful_tools.md
index 838c34c0b11..c67613017c9 100644
--- a/docs/useful_tools.md
+++ b/docs/useful_tools.md
@@ -310,7 +310,7 @@ Params: 37.74 M
 We provide a script to convert model to [ONNX](https://github.com/onnx/onnx) format. We also support comparing the output results between Pytorch and ONNX model for verification.
 
 ```shell
-python tools/deployment/pytorch2onnx.py ${CONFIG_FILE} ${CHECKPOINT_FILE} --output_file ${ONNX_FILE} [--shape ${INPUT_SHAPE} --verify]
+python tools/deployment/pytorch2onnx.py ${CONFIG_FILE} ${CHECKPOINT_FILE} --output-file ${ONNX_FILE} [--shape ${INPUT_SHAPE} --verify]
 ```
 
 **Note**: This tool is still experimental. Some customized operators are not supported for now. For a detailed description of the usage and the list of supported models, please refer to [pytorch2onnx](tutorials/pytorch2onnx.md).