The key audit matters are the most important matters that the auditor chooses to report from the matters communicated with the client's governance layer during the audit process in the audit report preparation stage when the quality of the audit results has been determined, to demonstrate the quality of the audit process and improve the communication value of the audit report. In practice, most of the reports on this matter tend to be similar. Is this a drawback of the auditor's reckless actions or a rational choice based on the quality of the audit results? Selecting A+H shares in 2016 and A-share listed companies in 2017—2019 as samples for research, it is found that the higher the quality of audit results obtained in the audit implementation stage, the smaller the difference in the key audit matters reported in the audit report stage, and the more important the affairs are. The smaller the scale, the more significant this relationship is. Further research finds that this strategic choice of auditors can reduce financial restatements and increase audit fees, which is indeed a rational behavior. The research conclusions are of great significance for auditors to correctly implement the key audit matter standards, for the government to properly supervise the key audit matter reports, and for investors to effectively use the key audit matter information.