In order to explore the relationship between the soil particle size distribution (PSD) with the soil microbial biomass carbon and nitrogen (MBC, MBN) contents for different community types, we chose three typical communities, which in Yanchi County of Ningxia desert grassland as the research object, to determine the changing characteristic of soil PSD ,the content of MBC and MBN in different soil layers (0-5,5-10,10-15 cm) of two soil habitat for different communities (Agropyron mongolicum Keng, Artemisia ordosica, Stipa breviflora). In addition,we analyzed the relationship between the composition of soil particles in sand, silt, clay particle volume fraction and the change of soil organic carbon (SOC), total nitrogen (TN) and MBC, MBN contents among different communities. The results showed that: (1) the soil particle size in different community types appeared tendency of “V” type distribution trend, but in Artemisia ordosica the soil particle content of 100-500 μm relatively more than that of other communities and has a significant difference. (2) The contents of soil SOC, MBC and MBN increased with the decreasing of soil depth, to a certain extent, in the same depth,the contents of soil SOC, MBN in canopy higher than that in pleous，which performed a“fertile island”, and at soil depth of 0-5 cm soil layer was significant difference (P＜0.05). (3) The correlation relationship between the composition of soil particle with soil SOC, MBC, SOC and MBN contents indicated that: the contents of MBC and MBN are high in wheatgrass, Stipa breviflora, which have a similar tendency with soil particle size of 0.01-2 μm, 2-50 μm, and 50-100 μm. The contents of soil SOC,MBC and MBN were showed significant(P＜0.05) correlation with the particle size lower than 100 μm. The contents of soil particle diameter 100-250 μm, 250-500 μm in Artemisia community showed a increased tendency, which lead to the lower contents of SOC, MBC and MBN; therefore,our result demonstrated that different community types not only have an influence on soil particle size distribution, but also have a significant impact.