"Hangwei Code" is a measure for COVID-19 to strengthen epidemic prevention and control by digital empowerment of big data, and its four-color code judgment changes dynamically based on the update of big data in the background of the system. For applicants applying for red, orange or yellow health codes, the reasons may be related to the fact that the confirmed or suspected cases are in the same space; May be related to coming from key epidemic areas; It may be related to countries or regions with medium and high risks; It may be related to physical discomfort when filling out the application form or punching in. If there is no abnormal behavior, it is recommended to wait patiently for a period of time, and the color of the health code may be updated.