The health code completes a very good impression entry point with the self-declared power and responsibility mechanism. Among the three types of users, for the general public, as long as there is a green code, they can pass, but for the business premises, as long as the general public provides a green code, the business premises have no responsibility. If there is a virus infection, the responsibility is also on the general public. In addition, the frequent use of health codes makes people realize that there are not so many COVID-19-infected people around them, thus creating a stable social atmosphere. Later, some functions such as real-time code brushing and trip tracking were added to the health code, and red, green and Huang San colors were used to indicate the degree of danger, which directly fitted people's impression of traffic lights. This is a very beautiful product.