Based on panel data of state-owned A-share listed companies in China from 2011 to 2021, this article examines the impact of non-state-owned shareholder governance on ESG performance and the moderating effect of green finance. Research has found that the governance of non-state-owned shareholders can improve the ESG performance of enterprises, and the development of regional green finance further strengthens the promoting effect of non-state-owned shareholder governance on ESG performance of enterprises. Further research has found that non-state-owned shareholder governance has a more significant promoting effect on ESG performance in state-owned enterprises with high participation of non-state-owned shareholders, participation of institutional investors, and central state-owned enterprises, and the regulatory effect of green finance has also been strengthened; Mechanism testing found that non-state-owned shareholder governance improves ESG performance of enterprises through governance effects, green innovation effects, and market signal effects. The research is of great significance to the sustainable development of state-owned enterprises under the new normal.