This study aimed to explore the changes and linkages of plant community species diversity and niche under different grazing intensities in （Leymus chinensis） meadow steppe， providing a basis for rational utilization of grassland resources. Taking plant communities in Leymus chinensis meadow steppe under six grazing intensities， including no grazing （G₀=0 cow.AU·hm^-2）， light grazing （G₁=0.23 cow.AU·hm^-2）， light-moderate grazing （G₂=0.34 cow.AU·hm^-2）， moderate grazing （G₃=0.46 cow.AU·hm^-2）， moderate-heavy grazing （G₄=0.69 cow.AU·hm^-2）， and heavy grazing （G₅=0.92 cow.AU·hm^-2）， as research materials， we conducted plant community surveys and calculated diversity indices and niche indices. The results showed that diversity indices first increased and then decreased with increasing grazing intensity， peaking at moderate grazing. The species importance values changed significantly， where the dominant position of Leymus chinensis was replaced by Carex duriuscula as the important values gradually decreased. The importance value was positively correlated with niche breadth， and the correlation was the strongest under light-moderate grazing and moderate grazing. The niche overlap value first increased and then decreased， while the interspecific competition pressure remained stable under light-moderate grazing and moderate grazing. Therefore， controlling the number of grazing livestock based on the niche breadth and overlap value of species could help stabilize the grassland ecosystem and facilitate the sustainable utilization of grasslands.

Grazing intensity  /  Species diversity  /  Niche breadth  /  Niche overlap  /  Meadow steppe