In recent years, China has made certain achievements in shallow sea petroleum geological exploration and development, but the exploration of deep water areas is still in the initial stage, and the water depth in the South China Sea is generally 500 to 2000 meters, which is a deep water operation area. Although China has made some progress in the field of deep-water development of petroleum technology research, but compared with the international advanced countries in marine science and technology, there is a large gap, in the international competition is at a disadvantage, marine research technology and equipment is relatively backward, deep-sea resources exploration and development capacity is insufficient, high-end technology to foreign dependence. In order to better develop China's deep-sea oil and gas resources, it is necessary to strengthen the development of drilling and completion technology in the oil industry drilling engineering. This paper briefly describes the research overview, technical difficulties, design principles and main contents of the completion technology in deepwater drilling and completion engineering. It is expected to have some significance for the development of deepwater oil and gas fields in China.