Following the companion paper on the laws of sediment size distribution which account for the effects of the measures of water and soil conservation as well as the geomorphologic factors, this paper further deals with the sediment reduction effect of conservation measures in different catchments. Not only is the total reduction load inflowing into rivers (including tributaries and the main stream) due to the measures of water and soil conservation discussed,but also the grading portions of reduced sediment load are predicted and verified by the measured data. The grain size corresponding to the maximum reduction of sediment yield in the non uniform suspended sediment particles is accurately predicted by the model, which is of great importance in the benefit analysis of the measures of water and soil conservation in various catchments.