According to the spatial scale,almost all of the soil erosion models can be classified as field-scale models,catchment-scale
models and region-scale models.Each type of erosion models has its distinctive characteristics.As to the field scale,the analysis of the clear vertical zones and the interaction between them is very important.In addition to the analysis of soil erosion on hill slopes,effects of runoff and sediment from hill slope on erosion and sediment at the followed gully zone and the erosion caused by gravity are complex and pivotal in the catchment scale.The sediment delivery has a significant importance to the erosion modeling.Establishing region scale erosion model,the relationship and the interaction of the subordinate drainages together with the style of the runoff yield and runoff concentration should be taken into account.In different scale,the influence of the main factors on runoff and sediment yield and the composition of the main factors is not the same.Commenting on the fitness and the existing problems of the popular erosion models home and abroad in these three scales will provide some useful suggestions for soil erosion modeling in the future.