According to Jacob externality theory, this study explores the impact of related variety on enterprise innovation, based on the data of quoted company from 2007 to 2013, this study utilizes PSTR model to test the nonlinear influence of related variety on enterprise innovation. The results show that: the related variety has a positive effect on the enterprises innovation; in the pace with the increasing of R&D investment, the related variety has a nonlinear impact on enterprise innovation. Different enterprise ownership has a different nonlinear influence of related diversity on related variety. In the pace with the increasing of R&D investment, the higher R&D investment leads to a stronger positive effect of related variety on related variety in middle and west areas.