The growing population, the transition dietary towards animal-based products, and the preference for the brand of grass-feeding livestock are bringing increasing pressure on natural grasslands, especially for dry-land areas. The Xilingol League of China is famous for its free-range livestock product, however, overgrazing and herders’ benefits damage are always serious issues for this semi-arid grassland region. This study focuses on the relationship between the supply of natural grassland and the consumption of free-range livestock in the Xilingol League, and this study employed the grassland carrying capacity as the index to judge the sustainability states and its trends of the local grass-feeding system. Satellite data production of net primary production was used for grassland production, statistical livestock data and the consumption model were used for actual forage consumption, and empirical key informant interview data were used to obtain a more comprehensive understanding. The results show that: (1) the natural grassland carrying capacity of the Xilingol League fluctuated, showing improvement from 2000 to 2021; (2) the grassland management needs to be more diversified in different regions with different natural conditions; and (3) while the demand for free-range, high-quality beef is increasing, attention should be paid to the carrying capacity of natural pastures and more consideration should be taken of the benefits of balancing the livelihood of herders, policy strategies, and the customers’ preferences. Potential ways of doing this include employing technologies to improve livestock production, and further exploring and promoting the economic value of the free-range livestock and the geographical indication to get the economic–ecological win-win situation. The research framework and results would be beneficial to reveal the potential threats in pastoral areas and provide support for the optimization of the regional grass-feeding breeding system, especially in middle-income countries.