Health code refers to the reflection of personal health status, mainly due to the outbreak of COVID-19 epidemic. In order to prevent the spread of the epidemic, all localities show their health status through modern technologies such as health codes. If there is a time-space intersection with the confirmed case, it is easy to change color and affect normal traffic. If there is any abnormality, it should be reported to the local epidemic prevention headquarters and the Big Data Bureau for timely correction.