Abstract: In order to validate the simulation formula for soil detachment rate and study systemically the relationship among soil detachment rate, discharge and slope, stream power, runoff scouring experiments were conducted at a large scale of slope gradient(3°～30°) and flow discharge (2.5～6.5 L/min). The results show that soil detachment rate is exponential function of slope gradient and flow discharge, and soil detachment rate increases with the increase of slope gradient and discharge. There is a remarkable correlativity among soil detachment rate, discharge and slope, the impact of discharge on soil detachment rate is bigger than that of slope gradient. Soil detachment rate increases in a linear function with the stream power increasing(R²=0.945, 9°≤S≤24°). Soil detachment occurs when stream power is more than 0.344 N/(m·s). Soil detachment rate can be predicted exactly by stream power.