Reusability is the key element in today’s VLSI design. Open-source hardware provides a more thorough and effective way for design reusability than traditional charged closed-source IP by sharing its design documents and IP modules. And open-source hardware based SoC design method is being accepted and practiced by more and more designers. This paper introduces relative concepts, benefits, problems and perspectives of open-source hardware in detail, and discusses open-source hardware based design flow in detail, and discusses open-source hardware based design flow in depth by exampling an open-sourceprocessor design.