About 47 of the 70 had been pulled from the rubble of the five-storey Xinjia Hotel by Sunday, state media says.
Videos posted online show emergency workers combing through the building's wreckage in the southern province of Fujian.
It is not clear what caused the collapse or if anyone has died.
It happened at about 19:30 local time (11:30 GMT).
Chinese state media says the hotel was being used as a quarantine facility monitoring people who had had close contact with coronavirus patients.
The hotel reportedly opened in 2018 and had 80 guest rooms.
One woman told the Beijing News website that relatives including her sister had been under quarantine there.
"I can't contact them, they're not answering their phones," she said.