Runoff plots are very important for soil erosion study.The measurement of sediment content is a key part in the process of soil loss calculation.It is so difficult for traditional measurement method to measure sandy particle that sediment content measured is apparently less than true value.The study was conducted in collecting tank at Shixia watershed

Miyun county of Beijing city.The six different sediment content including about 4

12

30

60

90

120 kg/m3 were put into collecting tank with about 0.7 m deep water

respectively.The traditional measurement method and layered measurement were used to measure sand content.The measurement results of these two methods were compared with true sand content.The results show that traditional measurement method underestimated sand content and the relative difference was (-83.05%)

while layered measurement method can precisely measure sand content and the relative difference was -2.77%.