Abstract: A field scouring experiment on soil erosion and sediment yield on unpaved roads was conducted to provide scientific date for predicting and controlling soil and water loss on unpaved roads. Results indicated that the variation of sediment yield appeared in three types, which were smooth, multimodal, and unmoral distribution on the condition of combination of same slope with different runoff discharges, or same discharge with different slopes. Spatial variation of sediment yield with slope profile could be showed reduction in three types, wave, gradual reduction and reduction after increase on the same road surface. The variations of average sediment concentration with supplied runoff discharge were accorded with logarithmic correlations. But, variations of sediment yield rate with supplied runoff discharges, average sediment concentration with slope, sediment yield rate with slope were accorded with linear correlation. The result was prospected to provide theoretical foundation for research and predication in the soil erosion of unpaved roads.