Based on the oretical analysis,field examination and investigation,it is considered that the 2.0t/ (hm² . a) is the rational soil loss tolerance of sloping field in semi-arid hill-gully area of the Loess Plateau during the long period according to soil formation velocity,top soil nutrient balance,land productivity stability in sloping field,sediment transport tolerance of the Huanghe River course,and regional economic development and so on.