A dual-box system(one is rill box and the other isf der box) with 15 gradient and clay loss is used to quantify effects of runoff and sediment from up-slope on down-slope rill erosion and sedunent under different sediment concentrations and rainfall intensities.The experiment results show,d that the sedunent from up}lope was completely transport,d, runoff from up-slope caused the additional sedunent deliv-ery at down}lope rill erosion channel. Sedunent regune in rill erosion process was always detachment一transport.The additional sediment delivery caused by up}lope runoff increased with a decrease of sediment concentration in up-silope runoff or an in- crease of rainfall intensity.