Abstract: The division of small watershed units in the Danjiangkou Reservoir Area is fundamental work for ensuring water qual- ity safety and building water ecological civilization in the reservoir area. We selected the Danjiangkou Reservoir Area (Shiyan Cit- y) in Hubei province as the research area and used high -precision DEM,high - resolution remote sensing images ,and other data sources. According to the 9 third - level watershed areas and 23 fourth - level watershed areas in Hubei province watershed com - prehensive governance and coordinated development planning outline , 1 472 fifth - level sub - watershed units were delineated , forming an important ecological function area small watershed division method for watershed comprehensive governance units by u- sing methods such as automatic river network extraction and human - machine interaction adjustment. The results can provide a decision -making basis for the prevention and control of soil erosion in the Danjiangkou Reservoir of Hubei province ,the evalua- tion of the effectiveness of small watershed management ,and the formation of a joint effort among various departments for soil ero- sion prevention and control.