In order to strengthen the prevention and control of epidemic situation in COVID-19, all schools require students and parents to have health code (green code) and travel code (green code), which must be accessed within 24 hours before the start of school. Submit travel records and health codes through the Internet in advance. Students who return to school outside the province must also submit proof of nucleic acid detection within 48 hours. If students have symptoms of fever, sore throat, cough or other infectious diseases, they need to postpone their return to school and return to school with the certificate of resumption of classes after recovery.