Anchoring on the shareholding structure, the A-share listed companies in Shanghai and Shenzhen in China from 2013 to 2019 was taken as a research sample, and the impact of reverse mixed ownership reform on the "greenwashing" behavior of private enterprises was discussed. Results show that by enhancing the financing capacity of enterprises, improving management's short-sighted behavior, and promoting enterprise' sense of responsibility for environmental protection, reverse mixed ownership reform can significantly alleviate the worsening problem about "greenwashing" behavior of private enterprises. The governance effects of state-owned equity was analyzed deferentially, the results show that reverse mixed ownership reform has a more significant inhibitory effect on selective disclosure compared to expressive manipulation. The quadratic term of reverse mixed ownership reform was introduced into the research to verify the existence of an optimal shareholding ratio for state-owned equity. Heterogeneity analyses revealed that governance effects of reverse mixed ownership reform in different contexts in terms of the nature of the industry, the degree of corporate disclosure, and corporate reputation. It puts forward relevant suggestions from three aspects, including that deepening the process of reverse mixed ownership reform in private enterprises, improving laws and suggestions on information disclosure, and strengthening the construction of corporate teams.