Herbivore grazing plays a critical role in shaping grassland ecosystems, yet its effects on the interplay between plant and insect diversity remain poorly understood, particularly in typical steppe environments. To address this gap, we examined the impacts of large-herbivore grazing on plant and insect diversity and their interrelationships in a typical grassland ecosystem. Insect communities were sampled using trapping and sweep-net methods across warm- and cold-season grazing areas. Our results showed that grazing treatments did not significantly alter plant species diversity but reduced plant biomass and cover while increasing overall plant diversity. A total of 3733 and 3671 insect specimens were collected from warm- and cold-season grazing areas, respectively, representing 12 orders and 44 families. Insect community diversity was negatively correlated with grazing intensity, but positively correlated with vegetation density and plant diversity. Environmental factors, particularly temperature, also shaped insect community structure by directly influencing insect growth and development. As grazing intensity increased, vegetation density declined-a change that positively affected Orthoptera (grasshoppers) but negatively impacted other insect taxa, suggesting top-down effects. These shifts may alter species diversity, trigger complex ecological interactions, and ultimately modify ecosystem functions such as food web dynamics. Our findings highlight the importance of considering both biotic and abiotic factors in understanding grazing effects on grassland biodiversity and ecosystem functioning.