Abstract: Taking Stipa breviflora as test material, the root secretion of components was identified, and then plant roots secretion solution was added to the soil, the effects of the different concentrations of exogenous root secretion（C0,C1,C2 and C3） on soil nutrients, enzyme activities and microbial biomass, soil microbial community functional diversity, the microbial metabolism entropy were studied, in order to explore the desert grassland of S.grandis community root secretion regulation mechanism of soil microbial community.The results showed that 21 species of root exudates were found in Stipa stipa, among which the esters were the highest, including 8 kinds of hydrocarbons, 10 kinds of esters, 2 kinds of phenol and 1 kind of ketone.Forty-fourbenzene alkyl（13.59%）,cis-9-octadecenoic acid-methyl ester（16.45%）,ethyl-5-octadecane（21.78%）,4,6-dimethyldodecane（12.78%）,1,2-xylene（10.34%） accounted for 74.94% of the total root exudates, desert grassland was short fancy stitch couchgrass root system secretion of main ingredients.The contents of organic carbon, total nitrogen and total potassium in root exudates with different concentrations were significantly higher than those of CK（P＜0.05） which were in turn as follow, C2＞C3＞C1＞CK,C1 and C3 were not significantly different（P＞0.05）.The activities of sucrase, catalase, urease, microbial biomass carbon and nitrogen content in soil treated with root exudates of different concentrations were significantly higher than those of CK,which were in turn as follows, C2＞C3＞C1＞CK,C1 and C3 showed no significant difference（P＞0.05）.Soil microbial species richness index, evenness index and carbon source utilization richness index were significantly higher than those of CK under different concentrations of plant root exudates（P＜0.05）,which were in turn as follows, C2＞C3＞C1＞CK,with no significant difference between C3 and C1（P＞0.05）.Redundancy analysis showed that the soil treated with medium concentration root exudates had similar metabolic characteristics to the soil treated with high concentration root exudates, which was significantly different from that treated with high concentration root exudates, indicating that they had different utilization ability of a single carbon source and their community metabolic characteristics were different.In general, the effects of root exudates on soil nutrients, enzyme activity, microbial biomass, functional diversity of soil microbial community, and microbial metabolism entropy showed a concentration effect of low promotion and high inhibition.