Exit and Entry Administration Law of the People's Republic of China

Article 38 Foreigners having reached the age of 16, who stay or reside in China shall carry with them their passports or other international travel documents, or foreigners' stay or residence permits, and accept the inspection of public security organs.

Foreigners who reside in China shall, within the prescribed time limit, submit foreigners' residence permits to public security organs under local people's governments at or above the county level in the places of residence for examination.

Article 39 Where foreigners stay in hotels in China, the hotels shall register their accommodation in accordance with the regulations on the public security administration of the hotel industry, and submit foreigners' accommodation registration information to the public security organs in the places where the hotels are located. For foreigners who reside or stay in domiciles other than hotels, they or the persons who accommodate them shall, within 24 hours after the foreigners' arrival, go through the registration formalities with the public security organs in the places of residence. 

Law of the People's Republic of China on Prevention and Treatment of Infectious Diseases

Article 39 …to keep the persons in close contact with the patients, pathogen carriers or suspected patients in medical agencies under medical observation at designated places and to take other necessary preventive measures. With regard to the persons who refuse treatment in isolation or, before the expiration of the period of isolation, break away from treatment in isolation without approval, the public security organs may assist the medical agencies by taking compulsory measures for treatment in isolation...

Article 41 With respect to the places where there are cases of infectious diseases under Class A or to the persons in the special areas within such places, the local people's governments at or above the county level where the above places are located may carry out isolation measures...

Frontier Health and Quarantine Law of the People's Republic of China

Article 12 A person having a quarantinable infectious disease shall be placed in isolation by the frontier health and quarantine office for a period determined by the results of the medical examination, while a person suspected of having a quarantinable infectious disease shall be kept for inspection for a period determined by the incubation period of such disease...