Since the financial crisis in 2008, countries have been exploring new ways to reform audit reports. Keeping pace with the reform of international auditing standards and significantly improving the information richness and communication efficiency of audit reports, China's Ministry of Finance issued the new Audit Reporting Standard No. 1504 in December 2016, which clearly stipulates that certified public accountants must disclose key audit matters and corresponding audit countermeasures in detail when preparing audit reports. To enhance the depth and transparency of the report. As the focus of the reform, the disclosure of key audit matters has put forward new requirements and challenges for CPAs and accounting firms. The openness of the audit process has increased the audit workload and the risk of CPAs being held accountable, but it has also become an opportunity for accounting firms to improve the quality of audit reports and establish a good reputation. In the context of the continuous disclosure of key audit matters, this paper studies the economic consequences of the disclosure of key audit matters, that is, the impact on audit fees, in order to provide feasible suggestions for the healthy development of the audit market.This paper selects China's A-share listed enterprises from 2017 to 2023 as sample objects, and conducts research from both theoretical and empirical perspectives. The results show that the number and length of disclosure of key audit matters have a positive impact on audit fees; In terms of the mediating role of audit delay, audit delay partly mediates the relationship between the number of key audit items disclosed and audit fees.