The rhizosheath of the arid zone grass comprises a dense cylinder of soil particles held mainly by short twisted root hairs. The formation of rhizosheath, one of the physiological adaptations of plant in the arid environment, was considered to be the result of the interactions among plant, microorganism and surrounding soils. The aim of this study was to elucidate the effect of Polysaccharides on the formation of rhizosheath in Agropyron cristatum L. based on the analysis of interactions among soil texture, Polysaccharides and characteristics of rhizosheath. The results showed that the soil aggregate structures were the direct reason of the rhizosheath formation. The polysaccharides played an important role in the formation of rhizosheath through its cementation, hydrophilic, water absorption and water retention by influencing the soil aggregate structure and proportion.