Taking the Hulunber meadow grassland in Inner Mongolia as the research object，the change law of the stoichiometric characteristics of soil microorganisms in different mowing frequency treatments was discussed so as to provide theoretical basis for the sustainable use of grassland resources.The six different mowing treatments were set up，including control(CK)，the one-cut-once-a-year treatment(M1)，the one-cut-every-two-years treatment(M2)，the one-cut-every-three-years treatment(M3)，the one-cut-every-six-years treatment(M6)，and the one-cut-every-twelve-years treatment(M12).Each treatment had three repetitions.Three quadrats were selected in each plot in the middle of August，2018，and three sampling points were randomly chosen，which were uniformly sampled at 0～10，10～20 and 20～30 cm，respectively.The soil samples were fully mixed according to the layers and brought back to the laboratory.After the samples were treated by chloroform fumigation，the soil microbial biomass carbon(MBC)，nitrogen(MBN) and phosphorus(MBP)were determined.The results showed that mowing treatments did not significantly affect the contents of MBC，MBN，MBP and their stoichiometric ratio，indicating that the microbial system had relative stability under mowing treatments.From the average values of the six treatments as a whole，the contents of MBC，MBN，MBP and the C∶N and C∶P of the microbial biomass(MBC∶N，MBC∶P)showed a trend of first increasing and then decreasing with the extension of the mowing interval，and reached the highest at M2 and M3.The average value of MBC∶P in each treatment in this experiment area was greater than 30，which was of a high ratio.The microbial biomass N∶P(MBN∶P)was lower than the global average level(6.9 or 5.6).Because the mowing in this study was generally carried out in the late growing season，the impact on grassland ecosystem was much smaller than traditional mowing，the impact on soil microbial biomass and its stoichiometric ratio was not obvious.However，appropriate mowing is not only conducive to microbial reproduction and root growth，also has a positive impact on grassland ecosystem productivity and vegetation community.That will affect the structure and function of grassland ecosystem.So grassland ecosystem should be properly mowed.