In this paper, "RS", "GIS" and "GPS" are integrated as the "3S" technology, which is widely applied to the construction of the dynamic monitoring system of soil erosion. This system is used to monitor the soil erosion in watershed and to pre-warn possible problems hidden in the process of land cultivation so that measures can be taken to prevent or solve such problems. At the same time, through the application of Chongqing dynamic monitoring system to soil erosion, functions and advantages of the system are explicitly presented.