Critical audit matters(CAMs)are expected by the standard setters to improve the audit quality and the company’s information disclosure level. The characteristics of CAMs can reflect the adequacy and appropriateness of the disclosure, thus reflecting the appropriateness of the disclosure of CAMs by listed companies. The results of event study show that, in general, the more the number and length of disclosure of CAMs, the more information content, but the stable conclusion only appears in the sample group of small companies with less alternative information sources. Therefore, as far as the current disclosure situation is concerned, the CAMs play a supplementary role only in small companies with less alternative information sources, while they have no information increment for large companies with relatively complete information disclosure, which indicates that the standards of CAMs need to be further refined and put forward higher requirements.