The "place code" is the only two-dimensional code given by a specific place, which represents the basic information such as the name, location and contact person of the place. On the basis of automatically verifying the "health code" information, the information of people entering the place can be automatically registered. Scanning the "location code" in the door is first to facilitate the masses to travel. The data of "site code" and "health code" are interoperable. Scanning the "site code" can automatically register people entering and leaving, and at the same time automatically verify the "health code" information, without having to show the health code repeatedly. The second is accurate traceability investigation. In the case of local epidemic situation, by scanning code records, we can quickly trace the activity track of relevant personnel, find close contacts in time, and win valuable time to avoid the spread of epidemic situation. The third is to protect personal information. Presumably, everyone has left their personal information on the visitor register of some units. In contrast, the application of "location code" can reduce the transmission level and leakage probability of personal sensitive information. More crucially, once a place involves the trajectory of COVID-19 infected people or other key personnel involved in the epidemic, the epidemic prevention department can quickly find the exposed personnel through the local code and control them, which is extremely important to prevent the spread of the epidemic.