Abstract:In the paper, we took the typical steppe in the west of Keshiketeng County in Inner Mongolia as the sample. We studied the seasonal changes of the quantity of soil microorganisms, soil microbial biomass of microorganism and the soil respiration intensity in light grazing district (LG), moderate grazing district (MG) and heavy grazing district (HG). We also observed the impact on these changes of different grazing intensity. The results show that the quantity of micro-organisms, the soil microbial biomass of microorganism and the soil respiration intensity are obviously changed with season, their highest values all appear in the August. There is obvious correlation between the three; light and middle grazing were beneficial to soil microorganisms, soil microbial biomass of microorganism increased, but heavy grazing have resulted in the quantity of soil micro-organisms and soil microbial biomass of microorganism reduction.