The ultra-light steel BIW of Baosteel (BCB) has reached the leading level in the proportion of lightweight and high strength steel, and has a leading position in technology for 3-5 years. BCB uses advanced materials and advanced technology which will be widely used in the next 5-10 years. It uses 7 kinds of advanced high strength steel materials. The proportion of high strength steel is as high as 77.5%. Through the combination of seven advanced technologies and processes, the lightweight index is 2.7, the vehicle weight is 284.1 kg, and the vehicle meets the advanced technology requirements of five-star. Compared with the same class of vehicles, the lightweight of 10% - 20% can be achieved. BCB shows the leading level of Baosteel in automotive steel research and application and Baosteel is also the first domestic supplier of automotive steel for the development of prototype vehicles.