The comprehensive control of soil erosion in small watershed is the soil conservation technique with Chinese features. The establishment of digital information system of small watershed management with 3S techniques should be based on the remote sensing and others, including the determination of catchment areas(10-20 km²) with the mountain ridges as boundary; drawing the small basin boundaries according to geographic information software and importing 18 figure small watershed code into computer. Because of the necessity of management, several small basin maps should be drawn according to the management patterns for the cities, counties or villages; for the basins or for the upper reaches of reservoir. Thus, the important basis is suggested to serve all grades of administration department to improve the management level of water and soil conservation.