Abstract: The small watershed division has become an important geographical unit in soil and water loss control,ecosystem restoration,etc.This paper takes the Chishui river basin as the research object,and obtains the digital elevation model(DEM)based on 1∶50000 topographic map,and then extracts the small watershed of the Chishui river basin in Guizhou province.We have carried out a field investigation combined with geological and hydrological data to verify the accuracy of small watershed division result.Eventually,we get 753 small watershed in the Chishui river basin of Guizhou province,most of them distributed in Xishui county,Chishui city,Renhuai city,Qixingguan cities,etc.Among the 753 small watershed,530 of them are part of complete type watershed,180 of them are part of interval type watershed,and 43 of them are part of slope type watershed.And there are 9 small watershed whose area is less than 3 km²,310 small watershed whose area between 3 km² and 10 km²,348 small watershed whose area between 10 km² and 30 km²,and 86 small watershed whose area between 30 km² and 50 km².The small watershed segmentation study of Chishui river basin in Guizhou province provides the scientific basis for small watershed management,the scientific basis for decision-making for the soil and water conservation measures of regional ecological construction,and promotes the soil and water conservation ecological environment construction.

Key words: Chishui river basin, digital elevation model(DEM), small watershed division, distribution