Whether regulatory inquiry on the part of exchanges leads to auditor’s voluntary resignation and whether there is a significant difference in audit pricing between the successor and the predecessor are worth studying.Based on this, this paper makes an empirical analysis on the annual reports and inquiry letters of A-share listed companies in Shanghai and Shenzhen stock exchanges from 2014 to 2019. The results show that there is a significant positive correlation between the annual report inquiry letter and auditor resignation. Compared with state-owned enterprises, non-state-owned enterprises receiving inquiry letters are more likely to resign auditors. The successive auditors will charge higher audit fees for enterprises receiving the inquiry letter and resigning the auditor. The research results not only enrich the Regulatory Utility Theory of inquiry letter but also expand the research boundary of auditing behavior of the successor and the predecessor, which is of practical significance to audit pricing of auditors.