Scientific and technological innovation system of Chinese offshore oil industry in terms of establishment background, developing phases, construction thoughts, main contents，practice highlights, achievements and leading functions was introduced. During the 30 years’ fast developing history, scientific and technological innovation system has been supporting the great leap of Chinese offshore oil industry. The China National Offshore Oil Corporation (CNOOC) makes its endeavor to promote scientific and technological innovative capacities and core competition abilities, complete the organizational, management and technological systems, in order to build scientific and technological innovation system of Chinese offshore oil industry supporting the fast and effective sustainable development of the corporation and realizing the aim of “building an international first class energy corporation”. During the practice process, the system shows many highlights with CNOOC characters, enhances the scientific and technological core competition abilities, and helps to establish a new offshore oil industry with Chinese characters, which makes contribution to safeguard the energy security, protect offshore interests and promote the development of the national economy in China.