The public opinion issues associated with major public health incidents have caused tremendous interference and impact on national prevention and control. In the public opinion communication channels, the cost of making rumors is low, and rumors can quickly spread the information through network media. Therefore, limiting the spread of information from the source and transmission channels can effectively cut off the spread of false information and opinions. This research is based on the blockchain tracing method to provide public security and epidemic prevention departments with the source of public opinion information and changes in the way of information dissemination during major epidemic events, so as to achieve control of public opinion. As far as the public is concerned, they can not only understand the real information of major public health incidents, prevent and control them, but also avoid the intrusion of rumors.