diff --git a/README.md b/README.md
index b6fc85a..d4305e4 100644
--- a/README.md
+++ b/README.md
@@ -23,6 +23,7 @@ All the models are implemented in pytorch or mxnet first, and export a weights f
 - [A guide for quickly getting started, taking lenet5 as a demo.](./tutorials/getting_started.md)
 - [Migrating from TensorRT 4 to 7](./tutorials/migrating_from_tensorrt_4_to_7.md)
 - [How to implement multi-GPU processing, taking YOLOv4 as example](./tutorials/multi_GPU_processing.md)
+- [Frequently Asked Questions (FAQ)](./tutorials/faq.md)
 
 ## Test Environment
 
diff --git a/tutorials/faq.md b/tutorials/faq.md
new file mode 100644
index 0000000..ea2d52b
--- /dev/null
+++ b/tutorials/faq.md
@@ -0,0 +1,89 @@
+# Frequently Asked Questions (FAQ)
+
+## 1. fatal error: NvInfer.h: No such file or directory
+
+`NvInfer.h` is one of the headers of TensorRT. If you install the tensorrt DEB package, the headers should in `/usr/include/x86_64-linux-gnu/`. If you install tensorrt TAR or ZIP file, the `include_directories` and `link_directories` of tensorrt should be added in `CMakeLists.txt`.
+
+```
+$ dpkg -L libnvinfer-dev 
+/.
+/usr
+/usr/lib
+/usr/lib/x86_64-linux-gnu
+/usr/lib/x86_64-linux-gnu/libnvinfer_static.a
+/usr/lib/x86_64-linux-gnu/libmyelin_compiler_static.a
+/usr/lib/x86_64-linux-gnu/libmyelin_executor_static.a
+/usr/lib/x86_64-linux-gnu/libmyelin_pattern_library_static.a
+/usr/lib/x86_64-linux-gnu/libmyelin_pattern_runtime_static.a
+/usr/include
+/usr/include/x86_64-linux-gnu
+/usr/include/x86_64-linux-gnu/NvInfer.h
+/usr/include/x86_64-linux-gnu/NvInferRuntime.h
+/usr/include/x86_64-linux-gnu/NvInferRuntimeCommon.h
+/usr/include/x86_64-linux-gnu/NvInferVersion.h
+/usr/include/x86_64-linux-gnu/NvUtils.h
+/usr/share
+/usr/share/doc
+/usr/share/doc/libnvinfer-dev
+/usr/share/doc/libnvinfer-dev/copyright
+/usr/share/doc/libnvinfer-dev/changelog.Debian
+/usr/lib/x86_64-linux-gnu/libmyelin.so
+/usr/lib/x86_64-linux-gnu/libnvinfer.so
+```
+
+## 2. fatal error: cuda_runtime_api.h: No such file or directory
+
+`cuda_runtime_api.h` is from cuda-cudart. If you met this error, you need find where it is and adapt the `include_directories` and `link_directories` of cuda in `CMakeLists.txt`.
+
+```
+$ dpkg -L cuda-cudart-dev-10-0 
+/.
+/usr
+/usr/local
+/usr/local/cuda-10.0
+/usr/local/cuda-10.0/targets
+/usr/local/cuda-10.0/targets/x86_64-linux
+/usr/local/cuda-10.0/targets/x86_64-linux/lib
+/usr/local/cuda-10.0/targets/x86_64-linux/lib/libcudadevrt.a
+/usr/local/cuda-10.0/targets/x86_64-linux/lib/libOpenCL.so.1.1
+/usr/local/cuda-10.0/targets/x86_64-linux/lib/libculibos.a
+/usr/local/cuda-10.0/targets/x86_64-linux/lib/libcudart_static.a
+/usr/local/cuda-10.0/targets/x86_64-linux/include
+/usr/local/cuda-10.0/targets/x86_64-linux/include/cuda_runtime_api.h
+/usr/local/cuda-10.0/targets/x86_64-linux/include/cudart_platform.h
+/usr/local/cuda-10.0/targets/x86_64-linux/include/cuda_device_runtime_api.h
+/usr/local/cuda-10.0/targets/x86_64-linux/include/cuda_runtime.h
+/usr/lib
+/usr/lib/pkgconfig
+/usr/lib/pkgconfig/cudart-10.0.pc
+/usr/share
+/usr/share/doc
+/usr/share/doc/cuda-cudart-dev-10-0
+/usr/share/doc/cuda-cudart-dev-10-0/changelog.Debian.gz
+/usr/share/doc/cuda-cudart-dev-10-0/copyright
+/usr/local/cuda-10.0/targets/x86_64-linux/lib/libOpenCL.so
+/usr/local/cuda-10.0/targets/x86_64-linux/lib/libOpenCL.so.1
+/usr/local/cuda-10.0/targets/x86_64-linux/lib/libcudart.so
+```
+
+## 3. .wts not prepared or not in the right directory
+
+If .wts file not in the right directory. The loadWeights() function will report error. Error logs like following.
+
+By default, the .wts file usually should be put in the same dir as `build`. For example, `tensorrtx/yolov5/yolov5s.wts`. And the .wts path defined in `yolov5.cpp`.
+
+```
+std::map<std::__cxx11::basic_string, nvinfer1::Weights> loadWeights(std::__cxx11::string): Assertion `input.is_open() && "Unable to load weight file."' failed.
+Aborted (core dumped)
+```
+
+## 4. yolo -s failed, class_num not adapted
+
+If you train your own yolo model, you need set the `CLASS_NUM` in `yololayer.h`. Which is `80` by default. Otherwise, you will get errors like following.
+
+```
+[Convolution]: kernel weights has count xxx but xxx was expected
+void APIToModel(unsigned int, nvinfer1::IHostMemory**): Assertion `engine != nullptr' failed.
+Aborted (core dumped)
+```
+