Regionalization of the key preventing and controlling area of soil and water loss is an important way to improve the effectiveness of prevention and controlling. By combining qualitative method with quantitative method and using technical means such as ArcGIS, a new round of regionalization of the key preventing and controlling area of soil and water loss in Jiangsu Province is carried out scientifically based on a comprehensive survey of the status of soil and water loss and obtained a map of regionalization of the key area. Results show that the key preventing and controlling area in the province consists of key preventing area and key controlling area, with a total area of 35 929 km² that accounting for 34.96% of the whole province. The two key areas are 21 934 and 13 995 km², accounting for 21.32% and 13.64% of the whole province, respectively.