The four - grandparents and their two grandchildren, aged five and seven - were in the two-story structure in Dangkou Village, Yihuang County when a landslide triggred by a rainstorm flattened it.
About 2.12 lakh people have been affected till today because of the downpour that started in Jiangxi on Monday. More than 3,000 people have been relocated, state-run Xinhua news agency reported.
Floods have destroyed 73 homes and damaged 12,000 hectares of farmlands, 2,200 hectares of which have been completely destroyed.
A rescue operation is under way.