Using the sample of Shanghai and Shenzhen A-share listed companies from 2015 to 2021, this paper explores the action direction, action mechanism and differentiated effect of enterprise tax burden on accounting information quality. The results show that reducing enterprise tax burden can significantly improve accounting information quality, which still holds after a series of robustness tests. Mechanism analysis suggests that reducing enterprise tax burden can improve accounting information quality through two mediating paths: reducing financing constraints and agency costs. Heterogeneity analysis shows that the improvement effect of reducing enterprise tax burden on accounting information quality is more obvious in companies with high tax payment contribution, short audit tenure and high analyst focus.