Abstract: Different temporal and spatial runoff rate, flow velocity and sediment yield in watersheds during the rainfall-runoff-soil erosion processes are of great importance for understanding the soil erosion mechanism. Their onsites and accurate measurements will provide theory data for physically based soil erosion simulation/prediction models. An automated system was presented in this paper for the measurements of the factors affecting soil erosion dynamic processes. The whole measurement system consists of weir and water level sensor systems, shallow water flow velocity measuring systems, sediment concentration measuring systems. The measuring system was set at every channel outlet and the typical points in the channels to obtain erosion dynamic processing in a laboratory watershed model. During 25 mm/h and 5 min rainfall period, the square correlative coefficients compared data logged by the system with the manually-measured ones to runoff and sediment concentration at the watershed outlet are 0.738 and 0.749, respectively, the flow velocity error is 8.7%. The results show that this system has higher feasibility and the accuracy. In the scope of accuracy, the data of runoff or sediment concentration at channels outlet were obtained, and flow velocities at typical points in channels were measured too. The measured results of runoff and sediment concentration in watershed indicate that the system is promising to be applicable in the study of soil erosion dynamic processes.