State broadcaster CCTV said at least 10 people were rescued from the debris, and that search and rescue operations were ongoing.
CCTV said the landslide occurred after 9am on Friday in Chongqing's Pengshui County.
Massive amounts of rocks and soil washed downslope, burying more than 10 residential buildings.
Images by CCTV showed part of a mountainside collapsing onto a residential area.
Several buildings were next to the collapse site, while rescue crews combed through the debris.
Rescue efforts were hindered by the unstable terrain and the ongoing risk of another landslide, according to the broadcaster.
Photos showed large slabs of rock sliding beside buildings into a waterway below.
Two buildings that looked about five and 15 storeys high were damaged but still standing.
The rain-triggered landslide occurred near a section of the Wujiang River, which cuts through mountains peppered with small towns and terraces.
Authorities said they sent more than 8000 disaster-relief items to Chongqing, including tents, folding beds and family emergency kits.
Several power poles were buried, disrupting power supplies.
Authorities said water, electricity and gas supplies were suspended within a 1km radius of the affected area to prevent further disruptions.
Pengshui County is in the southeast part of Chongqing, bordering the provinces of Hubei and Guizhou.
