In order to define the relationship between the soil mechanical composition and the nutrient in desert grassland, we studied four typical grassland communities in desert grassland of Yanchi Country, Ningxia. We analyzing the changes of soil particle size distribution (PSD) and the nutrient content of soil surface (0-5 cm), subsurface (5-10 cm), deep soil layer (10-15 cm) in different communities (Caragana korshinskii, Artemisia ordosica, Agropyron mongolicum,Stipa breviflora). We also explored the correlation of soil structure and soil nutrients. The results showed that: (1) soil particle size distribution of four typical grassland communities showed a trend of normal distribution, and significant difference in different communities(P＜0.05).The content of particle size of 100-500 μm had a significant influence of PSD. The different communities showed bigger difference than that of different habitats and different layers; (2) In addition to the total phosphorus(TP), soil nutrients decreased gradually with the increase of soil depth. The canopy is greater than the plexus and showed a special “fertilizer island effect” in desert grassland. And distribution characteristics of different communities showed: C. korshinskii＞S. breviflora＞A. mongolicum＞A. ordosica. The content of available nutrient was relatively higher and all communities reached the appropriate level; (3) Soil nutrient was significantly correlated with PSD. In addition to the available phosphorus (AP), the soil nutrients were positively correlated with soil fractal dimension (D). The particle sizes of 100-250 μm and 250-500 μm were significantly negatively or extremely significantly negatively correlated with the soil nutrients (P＜0.05 or P＜0.01). The clay and silt play a main role in the process of organic and inorganic cement and maintaining a good soil structure.