The auditor's practical characteristics have certain influence on accounting information quality of the audit. By using the data of A-share listed companies in China from 2005 to 2014 and accounting information comparability as research object, this paper makes an empirical analysis of the relationship between auditor's client importance and accounting information comparability from the perspective of auditor's client importance. The empirical evidence shows that the more the economic dependence of the accounting firm on a client, the lower the client's accounting information comparability can be. Similarly, the client importance of certified public accountants shows a significant negative relationship with the accounting information. Besides, client importance of accounting firms and certified public accountants have complementary relationship in the process of the formation of accounting information comparability.