Strategic emerging industries are in a critical period, and the formation of dominant design determines their future development path. The strategy of combining openness and exclusivity is playing an increasingly important role in helping enterprises achieve a dominant design. Then, how should enterprises formulate the corresponding “open-exclusive” strategy to promote the formation of dominant design? Based on this issue, an empirical analysis of how open innovation and exclusive mechanisms affect the formation of dominant design in strategic emerging industries was conducted, using patent and standard data from 283 enterprises. The results show that open innovation and exclusive mechanisms have different effects on the dominant design of strategic emerging industries, and open innovation has a significant promotion effect, while exclusive mechanisms will inhibit the formation of dominant design. Ambidextrous innovation has multiple mediating functions between open innovation and dominant design of strategic emerging industries. Exploitative innovation plays a mediating role between exclusive mechanisms and dominant design of strategic emerging industries. It conclusions reveal the internal mechanisms by which openness and exclusivity impact dominant design through ambidextrous innovation, which has significant managerial implications for enterprises seeking to secure a dominant design.