By the artificial rainfal experiment,the characteristics of surface runoff and sediment yield in loess and purple soil are contrastively studied under the same experimental conditions. Results show that loess slope belongs to the category of infiltration-excess runoff and deeper rills are developed on it. Purple soil belongs to the category of saturation-excess runoff,where rills are weakly developed or undeveloped. Erosion rate in loess is much greater than that in purple soil under the same conditions. When practicing soil conservation measurements,the appropriate methods combined with soil characteristics should be selected to achieve the ideal results.