Based on the data of GEM listed companies from 2012 to 2018， we examine the relationship among institutional ownership， innovation input and corporate performance from the perspective of how institutional investors influence corporate governance. We also explore the intermediary effect of innovation input in the process of institutional investors' influence on corporate performance. The study finds that institutional investors' ownership has a significantly positive correlation with corporate performance， and innovation investment plays an incomplete intermediary role between them， that is， the improvement of corporate performance by institutional investors is partly achieved by promoting innovation input. Further research shows that compared with unstable institutional investors， stable institutional investors are more able to participate in the company's production and operation decision-making actively， and have a more significant impact on innovation investment and corporate performance.