In order to reveal the soil stoichiometric characteristics and their driving factors under the two grassland utilization modes of enclosure and grazing, the enclosed and grazing grassland of the Ningxia Yunwushan in Guyuan were used as the research object, the soil stoichiometric characteristics of 0-30 cm layer and the influencing factors were quantitatively analyzed. The results showed that: (1) Enclosure decreased the soil penetration resistance, bulk density and moisture content, while increased the soil porosity. (2) In the 0-10 cm soil layer of the enclosed grassland, the main water stable aggregates were > 0.25 mm, and of which >5 mm water-stable aggregates accounted for 46%, the mean weight diameter (MWD) and geometric mean diameter (GWD) was 3.78 and 1.70, respectively, which were significantly higher than those of grazing grassland (P<0.05), but there was not significant in fractal dimension between enclosed and grazing grassland. The soil stability of enclosed grassland was improved. (3) The content of soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP) of the 0-10 cm soil layer in enclosed grassland was 17.714, 2.018 and 0.659 g/kg, respectively, which were all higher than those of grazing grassland, and the difference in TN was significant (P<0.05). (4) The soil carbon and nitrogen ratio (C/N), carbon and phosphorus ratio (C/P), and nitrogen and phosphorus ratio (N/P) of the 0-20 cm soil layer were all higher in enclosed grassland than those in grazing grassland. (5) SOC, TN, C/P and N/P were all significantly negative related to the soil bulk density and fractal dimension (P<0.05), and SOC and TN were significantly positive related to MWD and GWD in enclosed grassland (P<0.05). The correlation between soil stoichiometry and physical characteristics of grazing grassland was lower than that of enclosed grassland. Enclosure ameliorated soil physical properties and aggregate structure, improved soil nutrients. Soil stoichiometry was closely related to soil physical properties, and the soil physical structure might be the main control factor affecting soil stoichiometric characteristics.