Discussing the evolution law and interaction mechanism of innovation capability of main stream and new stream are of great significance for the enterprises to optimize the innovation capability sequence to achieve technological catch-up. According to the characteristics of the mainstream and new stream innovation, the innovation capacity sets are constructed, and then, the innovation activities of BYD''s traditional fuel vehicle and new energy vehicle are taken as research case. The evolutionary law of the enterprise’s mainstream and new stream innovation capabilities, and the function mechanism of mainstream innovation ability to the formation and promotion of new stream innovation ability are revealed.