Abstract: Based on the fact that soil microorganisms can enhance the adaptability of plants to global change, the effects of soil microorganisms on the ecological stoichiometric characteristics of rhizosphere soil microorganisms were studied under the background of nitrogen deposition, and then the regulation of changes in ecological stoichiometric characteristics on the soil microbial nutrient limitation was explored. Under the premise of soil sterilization treatment（sterilized soil（+S） and non-sterilized soil（-S））, one-year-old potted seedlings of Caragana korshinskii were inoculated in two ways（inoculation（+M） and without inoculation（-M））, and nitrogen addition treatments(no nitrogen application（CK）, low nitrogen(LN, 3 g·m^-2·a^-1), high nitrogen(HN, 6 g·m^-2·a^-1)) were set up. Compared with the original microbial community composition in non-sterilized soil without fungus inoculation, the correlation between ecological stoichiometric characteristics of microhabitat and microbial nutrient limitation under different treatments was explored. Results were as follows:（1）In sterilized soil treatment, the relative abundance of fungi in the rhizosphere soil of C. korshinskii mycorrhizal seedlings was significantly increased by 82.20%, 25.00% and 59.84% under CK, LN and HN treatments than that of non-mycorrhizal seedlings, respectively.（2）In the treatment of non-sterilized soil, the microbial biomass carbon-to-phosphorus ratio in the rhizosphere soil of non-mycorrhizal C. korshinskii seedlings under LN treatment was lower by 46.28% compared to CK treatment（P＜0.05）, while that of mycorrhizal seedlings was 56.76% higher compared to CK treatment（P＜0.05）.（3）Under the nitrogen addition treatments, stoichiometry of carbon and nitrogen-related soil enzyme activity, stoichiometry of carbon and phosphorus-related soil enzyme activity, and vector length in the rhizosphere soil of C. korshinskii non-mycorrhizal seedlings under sterilized soil treatment were significantly lower than those of mycorrhizal seedlings（P＜0.05）.（4）PLS-PM path analysis showed that the total effect coefficient of microbial regulation on microbial nutrient limitation was greater than that of nitrogen addition treatment. In summary, soil indigenous microorganisms and mycorrhizal fungi synergistically regulated the enzymatic stoichiometric ratio of rhizosphere soil, and enhanced the adaptation of soil microbial nutrient limitation to nitrogen addition.