The carbon cycle of grasslands grazed by herbivorous wildlife and human demand-driven domestic animal is a process of carbon uptake, storage and release in the coupled herbivore-grassland plant-soil system. Herbivores influence the grassland carbon cycle through grazing, trampling, and feces and urine return, but there remains significant uncertainty about whether they enhance carbon uptake and promote carbon sequestration or stimulate carbon release. This paper reviewed the possible effects and mechanisms of herbivores on the carbon cycle process in grassland, and proposes possible future research directions, with a view to providing a basis for the study of the carbon cycle process and mechanism in the alpine grassland of the Qinghai Tibetan Plateau, as well as the management of carbon sequestration. Research findings indicate that while alpine grasslands exhibit substantial net ecosystem productivity and carbon sink intensity, current results may overestimate carbon sequestration rates, influenced by observational site distribution and the impact of herbivores. Discrepancies exist among results derived from different methodologies. Carbon sequestration in alpine grasslands becomes more intricate under herbivore grazing. Herbivores significantly affect carbon storage and cycling in alpine grasslands by altering community composition, plant diversity, productivity, and above/below-ground carbon allocation. These effects are further regulated by climate and soil factors, introducing complexity and uncertainty. Current studies on carbon cycling in grazed alpine grasslands lack consideration of herbivore redistribution effects and intensity. Furthermore, the mechanisms of how vegetation carbon allocation responds to grazing intensity and the influence of grazing management on grassland carbon cycling necessitate further research. Future research should focus on the carbon coupling mechanisms among herbivores, vegetation, and soil, integrating field observations with process model simulations. Developing remote sensing-ecological process models for grassland carbon sink function management under various climate scenarios is crucial to propose adaptive management strategies for the evolution of alpine grassland carbon sink function.