In the face of widespread ESG information frictions in the capital market, will state-owned capital participation play an information governance role and thereby reduce the ESG rating divergence of private enterprises? To answer this question, this paper selects data from A-share listed companies in Shanghai and Shenzhen from 2009 to 2024 to empirically examine the impact of state-owned capital participation on the ESG rating divergence of private enterprises. The study finds that state-owned capital participation significantly reduces the ESG rating divergence of private enterprises. Mechanism testing shows that state-owned capital participation narrows the gap between different rating agencies in terms of information acquisition and interpretation capabilities by increasing the information content of enterprises and improving information quality, thereby reducing ESG rating divergence. Further analysis reveals that this inhibitory effect is more significant in sample groups where central state-owned capital participates, where state-owned capital in the same industry participates, where the geographical distance between the enterprise and the institution is greater, and where the ESG sensitivity of the industry is lower. Additionally, the role of state-owned capital participation in reducing the ESG rating divergence of private enterprises further enhances the efficiency of capital market pricing, and this is reflected in the reduction of stock price synchronicity. This paper enriches the research on the influencing factors of ESG rating divergence and the economic consequences of state-owned capital participation, providing certain references for further deepening mixed-ownership reform in the new era and improving pricing efficiency in the ESG investment field of the capital market.