The species-abundance pattern is an important reflection of community structure, which describes the distribution and number of different species within a community, and can better reflect the relationships among species and their mechanisms. It is a crucial way to reveal the nature of the community by tracing the mechanisms among species based on species-abundance pattern. A typical grassland in Inner Mongolia was selected as the object to analyze species-abundance patterns of the plant communities under grazing and mowing. Five niche models, the overlapping niche model (ONM), niche preemption model (NPM), broken stick model (BSM), dominance preemption model (DPM), and random allocation model (RAM), were used to fit the plant species. The objectives of this study were 1) to determine the relationship between species abundance and different land utilization patterns, 2) to explore the real distribution of plant communities under different utilization patterns by using mathematical models with different ecological significance, 3) to reveal the typical grassland community structure changes under different land uses, and 4) to provide the basis for the rational use of grasslands. The results showed that there were 33 species, 16 species, and 29 species in the mowing plot, grazing plot, and enclosed plot, respectively. Compared with the number of species in the enclosed plot, that in the mowing plot increased by 12%, while it decreased by 44.8% in grazing plot. The frequencies of the dominant species, Stipa grandis, Cleistogenes squarrosa, Anemarrhena asphodeloides, Leymus chinensis, and Carex korshinskyi in the mowing, grazing, and enclosed plots accounted for 88.33%, 81.47%, and 75.6%, respectively, of the total species community. The optimal fitting models were RAM (χ²=92.99, AIC=168.86, BIC=171.18) and NPM (χ²=22.29, AIC=246.17, BIC=250.27) for grazing and mowing plots, respectively, while the optimal fitting model for the enclosed plot was NPM (χ²=90.51, AIC=321.32, BIC=325.81). The model NPM had a better fitting effect on grazing utilization, and the RAM is less consistent with mowing and use of enclosures.