Abstract: Basin sediment yields were simplified into the yields from slope-area regions and gullies in this paper.A conceptual modelling for slope-area soil erosion was formulated.It was developed from the physically-based conception of which sediment yield of slope-area is equal to maximum sediment-carrying capacity of flow minus resisting erosive capacity of the soil over slope-areas.A conceptual formulation for gullieswas obtained by simplifying the Bagnold's function of river sediment discharge.They were proposed for the simulation of small basin sediment yields in loess regions of the Yellow River.The testing results was satisfactory by comparison with the observed data for the simulated sediment yields in eight small basins.