Based on the sample of A-share non-financial listed companies from 2009 to 2019, this paper uses a difference-in-difference model to investigate the impact of D&O insurance on the internal control deficiencies and its mechanism, and tests the regulatory role of Party governance on the relationship both it. We find that D&O insurance have a significantly positive effects on the internal control deficiencies. Specifically, it increases the ratio of whether internal control deficiencies by 26.91%, while the party organization can significantly alleviate the adverse effects. Mechanism shows that D&O insurance plays a negative roles in the internal control by damaging the internal environment, risk assessment, control activities and internal supervision. And party organization has a negative effects on the relationship between D&O insurance and these four elements.