The soil loss.sediment yield and process as well as soil anti-scourability were tested on field artificial runoff plot and undisturbed soil sampling(lOcmX20cmXlOcm)under the same conditions.The result showed that soil sample washing method was 200-400times of soil loss than in the runoff plot in 15 minutes with rainfall of 0.65 and 0.84 mm/min.The erosion process in soil sample washing was different from in runoff plot.The runoff depth in former was 50~150 times and erosion modules was 5-7times(bare land)and 1.8-4.5 times(pasture)of in runoff plot.The reason of such difference was analysised.It was also found that there exited relation of sediment yield between samples of large size(lOcmX20cm XlOcm)and small size(3.5cm X 20cm X 4cm), and sediment yield in former can be estimated by small one.