The accident happened around 8am in the village of Zhenhe, located in Yiliang County of Zhaotong City, the county government said.
The landslide, estimated to be around 10,000 cubic meters, engulfed a primary school building, trapping 18 students, the government said.
Two residences near the school were also hit by the landslide, with one villager being buried. A family of three managed to escape the landslide before it arrived.
The government has moved local residents to safer places and dispatched rescue teams to the area.
On September 7, multiple earthquakes struck Yiliang County and its neighbouring areas in Yunnan and Guizhou provinces, killing 81 people and injuring 800 others.