The incident took place at 10:20 am in Hedao village, Fengzhuang township in Yanjin County.
Thirty-seven people, most of them women, were lifting the building's foundations when it toppled. Twenty-one people have been rescued from the collapsed building, state-run Xinhua news agency reported.
Rescue efforts are on.
The construction team's head has been taken into custody, the report said.