Based on the sample data of listed companies in China from 2010 to 2020, and on the perspective of corporate social responsibility, this paper discusses the influence of common institutional ownership on listed companies and its mechanism. The results show that common institutional ownership can significantly improve the performance of CSR. After a series of robustness tests, the conclusion still holds. Mechanism analysis shows that common institutional ownership improves corporate social responsibility performance through institutional synergy and supervisory governance effects. Further discussion shows that common institutional ownership plays a more significant role in promoting CSR performance in long-term shareholding, immature enterprises, capital market in the “bear market” stage, non-state-owned enterprises and manufacturing enterprises.