Internal control audit in China has experienced the transformation from voluntary rules to mandatory rules. Taking the companies conducting internal control audit from 2007 to 2021 as samples, this paper studies the relationship between internal control audit and accounting information value correlation under different rules. It is found that compared with the voluntary internal control audit, the mandatory rules weaken the value relevance of accounting information. Mandatory rules differ in the impact of audit opinion type and audit mode on the relevance of accounting information value. The earnings quality, the institutional investor and the analyst focus can alleviate the negative impact of the mandatory rules of internal control audit on the value relevance of accounting information. The results show that under the current situation of mandatory audit rules, companies should pay attention to the incremental value brought by independent audit mode while strengthening the construction of internal control to obtain unqualified audit opinions. Improving the quality of earnings and giving full play to the role of institutional investors and analysts will also help alleviate information asymmetry and improve the value relevance of accounting information.