Grasslands play an indispensable role in global ecological balance. However, land utilization practices such as mowing, grazing, and mining have led to degradation, affecting plant diversity and reducing carbon (C) and nitrogen (N) stocks. Revealing these degradation mechanisms after various land utilization practices is essential for implementing effective management practices to restore and sustain degraded grasslands. This study examines the effects of different land use types-mowing, light grazing, heavy grazing, and mining-on plant community characteristics, biomass, soil C and N dynamics in the Hulunbuir Grassland of Inner Mongolia. Our results revealed that across 50 herbaceous species, dominant vegetation shifted significantly: light grazing favored native grasses like Cleistogenes squarrosa and Artemisia frigida, while heavy grazing and mining promoted invasive species (e.g., Taraxacum mongolicum). Plant diversity and biomass were highest under mowing, but mining reduced species richness by 35 % and biomass by 50 % compared to mowing. Soil organic carbon (SOC) and total nitrogen (STN) stocks varied significantly across land-use types and plant growth phases, peaking in mowing sites (SOC: 9.85 f 1.45 g/kg; STN: 1.55 f 0.05 g/kg at 0-20 cm depth) and declining sharply in mining areas (SOC: 3.44 f 0.46 g/kg; STN: 0.76 f 0.06 g/kg). Strong correlations linked plant diversity and root biomass to SOC and STN retention, whereas Asteraceae biomass showed minimal influence. Structural equation modeling demonstrated that land use influenced SOC and STN stocks primarily through indirect effects on plant, root, and litter biomass rather than direct impacts. These findings underscore the need for daptive, site-specific restoration frameworks to mitigate degradation, prevent invasive species encroachment in mining areas and grazing livestock for sustainable grassland restoration.