Using the data of A-share non-financial private listed companies from 2008 to 2020, this paper explores the impact of the reverse mixed ownership reform on the tendency of auditors to issue modified audit opinions. The reverse mixed ownership reform is measured by the shareholding ratio of the state-owned capital among the top ten shareholders and the 10%  exceeding ratio of the state-owned shareholders. The results show that the reverse mixed ownership reform is significantly negatively related with modified audit opinion. The results of mechanism tests demonstrate that the reverse mixed ownership reform partially reduces the tendency of auditors to issue modified opinions by improving accounting information quality and decreasing business risk. The heterogeneity tests show that the impact of reverse mixed ownership reform on audit opinion only exists in the companies with higher information asymmetry and weaker regional legal environments and when the client importance at accounting firm level is lower. Besides, the negative effect of reverse mixed ownership reform on audit opinion mainly comes from the shareholding of nonfinancial state-owned entities institutions. This study can not only enrich the research on the economic consequences of reverse mixed ownership reform from the perspective of audit opinion, but also deepen the understanding of the relationship between ownership structure and auditor's decision behavior.