Runoff processes simulation is very significant for soil erosion mechanism analyzing and erosion model building.In the past
two decades,many runoff simulation model were built in China based on different conditions,however,they were difficult to qpply widely.Therefore,building one new model is necessary.In order to find one easy and exact way to simulate runoff process on slope land,9 simulated rainfall experiments were carried out on one plot with 10mlength,2m width and 15 degree at Ansai field station.Soil physical properties are the basic information to influence soil infiltration and runoff appeating.So soil physical properties were measured using 2 soil samples taking from polt for dach rainfall event by means of STAR-1 and unsaturated soil arameters, which was analyses by Appia program, were obtained.Those parameters were used to calculate soil absorptive parameter S f.And then,the modified Green &Ampt infiltration model,Retention Curve method and
kinematic wave model were used to simulate runoff processes.The results indicate that using
unsaturated soil physical properties to simulate runoff processes are available and the relative errors vary from 11.0 to 30.7%,However, more 80% simulated drror are less than 18 percent and it demonstrates using unsaturated soil physical properties to predict runoff process is reasonable and should be used widely.