The experiment on the effect of grazing on the asexual and sexual reproduction and biomass allocation in Leymus chinensis population was conducted in Songnen grassland. The results show that animal grazing reduced both asexual and sexual reproductive channels. With the increase of grazing intensity, the densities of asexual shoots and rhizome tillers, seed biomass, numbers of seeds per inflorescence and sexual shoot ratio decreased significantly, especially after heavy grazing. The rates of biomass allocation to rhizome increased significantly with increasing grazing intensity, while the rates of biomass allocation to assimilation, unassimilation organs and seed production decreased remarkably. In the haviest grazing stage, there were almost no sexual shoots.