Against the backdrop of mandatory ESG disclosure regulations, enhancing the quality of ESG disclosures through the synergy of audit assurance and legal compliance has become a crucial driver toward promoting efficient capital market operations. Addressing the current imbalance between the market-based credibility enhancement logic of audit assurance and the administrative control logic of legal compliance in ESG disclosure, this study constructs a three-dimensional ESG disclosure linkage mechanism, including comprising rules, processes, and accountability based on collaborative governance theory. Research findings indicate that a collaborative governance mechanism where legal compliance establishes rigid institutional boundaries while audit assurance provides flexible professional support can effectively drive ESG disclosure from formal compliance to substantive effectiveness, achieving a governance leap. This study clarifies that the boundaries of authority and responsibilities within ESG information governance, along with the logic of collaboration, providing theoretical support for curbing greenwashing in capital markets and refining the Chinese distinctive ESG regulatory framework.