Abstract: Stipa Baicalensis is one of regional herbs in the eastern Inner Mongol and the western Northeast China.Throug h an art if icial simulation experiment, the "fertilizat ion" effect of CO₂ concent ration enrichment on Stipa baicalensis is analyzed.The results show that the biomass and growth value of the herbage, the Pcontent in the root, and C, N, P contents in the leaves increase with CO₂ concentration enrichment.The impacts of soil drought stress on the biomass and grow th value are all negative.Mo reover, the impact is more remarkable with the agg ravating drought deg ree.Soil drought increases C, N contents in the herbage leaves and roots.