Abstract: The article takes the supply chain enterprises of A-share state-owned listed companies from 2009 to 2022 as the research object， and based on the synergy theory of public governance and corporate governance， systematically examines the spillover effects and mechanisms of national audit on the ESG performance of supply chain enterprises. Research has found that national audits have a significant promoting effect on the ESG performance of supply chain enterprises， and this conclusion still holds true after a series of robustness tests such as parallel trend testing， placebo testing， PSM-DID， and Heckman two-stage testing. Mechanism testing found that national audits enhance the ESG performance of supply chain enterprises by applying imitative pressure， mandatory pressure， and normative pressure. The research not only expands the theoretical boundaries of audit spillover effects， but also provides policy insights for government departments to promote supply chain ESG collaborative governance through vertical regulation.