This study aimed to elucidate the effects of varying grazing intensities on soil active organic carbon fractions and their environmental driving mechanisms in the typical steppe of Xilingol League， which could provide empirical support for carbon management strategies in grassland ecosystems. Three grazing treatments—no grazing （CK）， moderate grazing （MG）， and heavy grazing （HG）—were established in the experimental area using a completely randomized block design with five replicates per treatment. Soil physicochemical properties， soil organic carbon （SOC）， and its active fractions were quantified and analyzed. Compared to CK， MG significantly decreased the contents of particulate organic carbon （POC） and microbial biomass carbon （MBC）， but significantly increased the easily oxidizable organic carbon （EOC） content. The HG treatment significantly reduced the contents of POC and dissolved organic carbon （DOC）. Furthermore， POC and MBC contents under MG were significantly higher than those under HG. SOC exhibited a highly significant positive correlation with all its active fractions （P<0.05）. Soil water content （SWC） and total nitrogen （TN） were identified as the key factors influencing SOC and its fractions. Overall， grazing reduced the contents of SOC and its active fractions in the typical steppe. Therefore， avoiding heavy grazing is recommended. Incorporating soil moisture regulation and moderate nitrogen supplementation during pasture utilization can enhance soil carbon sequestration， thereby maintaining soil quality and carbon pool functionality.

Typical steppe  /  Grazing intensity  /  Active components of soil organic carbon  /  Biomass