In addition to the green code, there are yellow code and red team, which respectively represent different meanings: First, the green code means safer. Second, the yellow code: indicates that you have been to an unsafe area. 3. red team refers to contact with confirmed, suspected and asymptomatic infected persons. The color of health code is influenced by the following factors: First, the spatial dimension. According to the national epidemic risk and relevant data, big data companies can accurately go to towns (streets).