Applying the artificial precipitation experiment, the slope surface runoff and sediment yield characteristics of loess and purple soil under same experimental condition have been contrastively studied . The study results show that, loess slope belongs to excess infiltration runoff production, deeper erosion gully is developed ； purple soil belongs to excess saturation runoff production, slope channel is developed weakly or undeveloped. Under same condition the slope erosion yield of loess is much greater than that of purple soil. When we are working out soil conservation measurements, appropriate method should be selected according to soil characteristics to achieve the ideal results.