The productivity and allocation of nutrient elements and the biological nutrient cycling in two typical grasslands in the Xilin River Valley,Inner Mongolia were studied.Results obtained showed that the above-ground biomass was about 210g·m^-2.in Aneurolepidium chinense steppe (A.C.S.) and around 140-170 g·m^-2 in Stipa grandis steppe(S.G.S.).The under-ground biomass was 2837g·m^-2 in A.C.S.and 1596g·m^-2 in S.G.S.(0-100cm) in 1985,and 1627 and 870g·m^-2(0-70cm) in 1986,respectively.The Root/Shoot ratio varied from one grassland type to another and from year to year being in the range of 5-12.