Health code is to judge the individual's trajectory according to big data. Few people have lied about information before. Compared with personal consciousness, it is as important to use big data technology to quickly compare false information. This also puts forward higher requirements for the previous information collection work, especially for towns, communities and other information that have mastered the "last mile of epidemic prevention" to enter the data cloud. With a comprehensive and solid database, there will be no false information that escapes. At the same time, the epidemic situation is changing all the time, so it is necessary to update the cloud data on which the "health code" depends in real time and correct the personal health code information in time to make the "health code" model more accurate and reliable.