As the continuous expansion of the resources development of offshore oil and gas, more subsea well will be used at domestic offshore oil and gas fields, yet there is still no supporting technology and equipment for subsea well intervention in China. This paper compare the technology of well intervention and workover, introduce two kinds of light well intervention systems, compare their advantages and disadvantages, and then analyze the development and operation of subsea well intervention systems in the world. The development gap and countermeasures of related technologies in China will be summarized, at the end.