This paper applies the WEPP model to simulate soil erosion and spatial variation in Sichuan hilly basin.The study was carried out on six cultivated slope lands and fifteen bare slope lands.As to single storm

the average relative error of six cultivated slope lands is 25.5%.The relative errors less than 30% account for 88.9% of all the errors of those six cultivated slope lands.The average error of fifteen bare slope lands is 20.3%

the relative errors less than 30% account for 86% of all the errors of those fifteen bare slope lands.The relative errors of annual soil erosion in 2004 and 2005 are 14.94% and 14.37%

respectively

which is less than those of single storms.So the WEPP model is more suitable to simulate soil erosion in long time scale.The WEPP model is also able to simulate the spatial variation of soil erosion.By means of sloping erosion curve

the erosion area can be divided into three parts: erosion developing part

erosion accelerating part and main erosion part.The length of erosion accelerating part has negative relation with rainfall and rainfall intensity

while the length of accelerating part and the erosion has positive relation with the length of slope.