With the gradual development and improvement of China's securities market, the phenomenon of the change of accounting firms in listed companies is becoming more and more common, which has attracted the attention of regulators, the media and the public. At present, there are a large number of empirical studies on the change of accounting firms and accounting conservatism of listed companies in domestic and foreign, but most of them don't combine the two together. Based on this, this paper makes an investigation on the influence of the change of accounting firms on accounting conservatism and makes a research on different types of changes, with all the listed companies in Shanghai and Shenzhen A-share markets from 2010 to 2014 as the research object. It is found that the change of accounting firms in listed companies will decrease the accounting conservatism.