The landslide hit early morning and buried 29 people in the village of Pianpo, in the southwestern province of Guizhou, local authorities said.
Nine were pulled from the rubble, one of whom later died and the eight others hospitalized, it said. Rescue efforts were continuing, it added.
Pictures posted online showed a deluge of mud had toppled trees and crushed cement buildings, leaving bricks and cinder blocks scattered in heaps of rubble. Rescue workers with hard hats and shovels dug at steep slopes of debris.
Flooding is common during the summer monsoon season in southern China, but rainfall has been particularly heavy this year and many areas have been lashed by torrential rains this week, according to AFP.
China's national observatory issued an orange alert for storms across the country's south and east Thursday -- the second highest warning in a four-tiered system -- and told people to take precautions against possible flash floods and landslides.
Whole villages were leveled and at least 98 left dead in the eastern province of Jiangsu last week after the region was hit by a storm with hurricane-force winds and the worst tornado in half a century.