On arrival, the first check you have to pass is the Quarantine Check. 

At the check point, you show your passport and the form you filled in on board. Anyone with listed diseases such as yellow fever, cholera, VD, leprosy, infectious pulmonary tuberculosis or AIDS will be forbidden to enter or be sent to the airport clinic for further checking. 

Those arriving from areas with epidemics yellow fever must show their valid certificates of inoculation against this disease. Those with symptoms of fever, diarrhea, vomiting or rashes must declare this information accurately. 

For those who are going to stay longer in China, they have to show their quarantine certificate issued by an authorized health department abroad.