Abstract: Vegetative filter strips（VFS）are areas of permanent vegetation established between agricultural field borders and waterways,which have been recommended as one of the best management practices for retaining nutrients and sediments from surface runoff. Grass filter strip is a common type of VFS for its tall,erect,stiff-stemmed and native perennial grasses. Many laboratory and field studies indicate that grass filter strips can significantly reduce sediment and nutrient loss in runoff,while grass filter strip functions as a natural terrace,where sediment and other pollutants are removed from runoff by infiltration,deposition,absorption,adsorption,decomposition and volatilization.Natural rainfall,simulated runoff and simulated rainfall are the main experimental ways to investigate pollutants interception in VFS. The advantage of simulated rainfall experiments is the ability to control VFS scale,rainfall parameters and underlying surface conditions,thus the data obtained from simulated rainfall tests is generally less variable and easier to interpret. The study is conducted at an experimental plot next to Kunyu River in Beijing. The plot is an area of 4 m by 14 m with a slope of 5.0%. The plot is divided into two parts,including one simulated rainfall run-off generation area（4 m by 2 m）as the pollutant source area and one runoff transport area（4 m by 12 m）as the treatment area. There are four treatment strips in runoff transport area. One strip is the control system without vegetation,while the other three strips are parallel grass filter strips with the same vegetation composed of bermuda,tall fescue and white clover. A series of simulated rainfall experiments are designed to compare the transport of pollutants from strips with and without vegetation. This study aimsat evaluating the interception effects of the grass filter strip on suspended solids,nitrogen and phosphorus in the surface runoff formed by rainfall hydraulic erosion so as to provide a reference for pollutants trapping in the grass filter strip. The results show that:（1） In three simulated rainfall experiments,the outflow concentrations of SS,NH₄⁺-N,TN,TDP,TP and COD_Mnfrom grass filter strips are less than those from the control system significantly,except for NO₃^--N. Grass filter strips have no significant effect on NO₃^--N concentration reduction. （2） Compared to the control system,the average outflow concentrations of SS,NH₄⁺-N,TN,TDP,TP and COD_Mnfrom grass filter strips has decreased by 80.80%,12.23%,39.33%,12.46%,61.44% and 83.34% respectively. （3）There existed particulate and dissolved forms of pollutants in the surface runoff. Grass filter strips have more efficiency in the concentration reduction of particulate pollutants such as SS and COD_Mn,compared with dissolved pollutants such as NH₄⁺-N,TDP and NO₃^--N. The contents in TP and TN are sediment bounds,thus their concentration reductions are higher than dissolved pollutants. In dissolved pollutants,the concentration reductions of NH₄⁺-N and TDP with stronger absorptivity are higher than NO₃^--N with weaker absorptivity. The results indicate that the grass filter strip is an efficient measure for reducing contamination from non-point source pollutants deriving from soil erosion when rain falls.