Riparian vegetated filter strips (RVFS) are an efficient approach to reduce agricultural non-point source pollution transported in runoff before the water flows into watercourses. A field scale study was conducted in the upper reaches of Liaohe river for two years to determine the effect of vegetation types and the width on nitrogen and phosphorus retention in subsurface seepage. The experimental site consisted of three plots adjacent to agricultural edge (weeds-T1

sweet clover (Melilotus suaveolens L.)-T2 and sweet clover (Melilotus suaveolens L.)/China wingnut (Pterocarya stenoptera C. DC.)-T3). T2 and T3 were new established filter strips that were compared with weeds (T1). The results showed that all the RVFS did not significantly reduce the concentration of ground water nitrogen and phosphorus except for NH4+-N

The average interception efficiency was 18.03%~62.20%. The 13 m T3 had the best retention effect for NH4+-N which was 77.45%.T3 had the highest retention efficiency of TP and DP for 62.15% and 80.01% at the 13 m width. The overall T3 on the various forms of nitrogen and phosphorus retention effect is best

followed by melilotic belt. The plant vegetation filter on nitrogen and phosphorus accumulation capacity was Pterocarya stenoptera>Melilotus>weeds. Taking a harvest for sweet clover

the mount of nitrogen removed by the above-ground part varied in the range of 15.21~26.78 g/m2

and the phosphorus was in the range of 0.72~1.27 g/m2 .