Taking the provincial data from 2012 to 2023 as samples, this paper uses the multi-period DID model to study the impact of the national-level big data comprehensive pilot zone on the national audit effectiveness. The results show that the big data experimental area significantly improves the national audit effectiveness, and this conclusion is still valid after a series of robustness tests. Mechanism analysis shows that digital economy policy support, audit technology innovation and data element configuration are important variables for big data pilot zone to improve national audit effectiveness. Heterogeneity analysis finds that in the regions with strong independence of audit institutions and strong anti-corruption efforts, the big data pilot area can significantly improve the national audit efficiency. Furthermore, the study also examines the economic consequences from different dimensions of debt risk and national audit function. The research conclusions have certain reference significance for empowering national audit effectiveness with digital elements.