The intercepting rainfall of grassland of Astragulus adsurgens in loess hilly region wasstudied by using weight method in this paper.The result showed that there was an equatoin as fol-lows,p_j=-0. 0186 + 0.0601CIt-0.00612C²I²t² among interecepting rainfall(P_j),grasslandcoverage(C),rain intensity(I),and rain time(t).The maximum intercepting rainfall rate was29.7%. Meanwhile,the impact of coverage,rain intensity and rain time on intercepting rainfall was discussed.