[Objective] The relationships between community characteristics, species diversity, and soil physical and chemical properties of Carex duriuscula in Hulunbeier steppe were analyzed in order to provide a scientific reference for the protection and restoration of grassland ecosystems. [Methods] Ninety-five sample plots typifying the Hulunbeier C. duriuscula steppe were studied. The relationships between community characteristics of four community types and species diversity and soil physical and chemical properties were studied. [Results] ① With regard to the community characteristics, aboveground biomass, species richness, and Shannon-Wiener index were significantly different among the four community types. The community of C. duriuscula-annual and biennial herbs was the highest. With regard to the soil physical and chemical properties, total nitrogen and total phosphorus were the highest in the community of C. duriuscula-rhizome herbs. ② Soil organic carbon, total nitrogen, and total phosphorus were significantly positively correlated with above-ground biomass and below-ground biomass in the C. duriuscula-clump herbs community and the C. duriuscula-forbs community. ③ Soil organic carbon, total nitrogen, and total phosphorus were significantly negatively correlated with the Shannon-Wiener index, Simpson index, and Pielou index in the C. duriuscula-rhizome herbs community and the C. duriuscula-annual and biennial herbs community. [Conclusion] There were differences in community characteristics among the four community types in the C. duriuscula steppe. Soil organic carbon, total nitrogen, and total phosphorus were the main factors affecting the differences in community characteristics and species diversity.