By application of statistic theory,we provide experiment formulas of rainfall-runoff and rainfall-sediment for different branches based on the study of regulation on runoff and sediment discharge of main twelve branches located in Weihe watershed and statistic analyses of rainfall,runoff and sediment data.We apply the formulas to calculation of the benefits of decreasing runoff and sedinvent of control measures of soil and water conservation under each branch from 1970s to 1980s,a reliable preliminary result has been obtained.It provide scientific basis for control planning,reasonable development and utilization soil and water resources.