Under the dual impact of global climate warming and human activities, grasslands in arid and semi-arid regions are undergoing irreversible degradation. Inner Mongolia’s grasslands, located in a dry region highly sensitive to global climate change, are facing a critical need for protection against the influences of both natural and human factors. However, effective grassland preservation hinges upon a comprehensive understanding of the primary drivers behind grassland growth status in arid and semi-arid regions. Despite recognition of this imperative, consensus on the precise driving factors and mechanisms governing Inner Mongolian grasslands remains elusive within the scientific community. To bridge this crucial gap in knowledge, we conducted an in-depth analysis of grassland dynamics in Inner Mongolia spanning from 1990 to 2015. Leveraging a diverse array of datasets including remote sensing imagery, meteorological records, basic geographic information, and statistical yearbook data, we meticulously examined the temporal trends in grassland growth. Employing advanced analytical tools such as geographic detectors, we systematically compared the impacts of various driving factors on Inner Mongolia’s grasslands. Furthermore, we employed a structural equation model to delve into the underlying mechanisms governing the variation in the Normalized Difference Vegetation Index (NDVI) across different grassland types. This comprehensive approach enabled us to elucidate the complex interplay between environmental variables and grassland dynamics, shedding light on the key drivers shaping the health and resilience of Inner Mongolia’s grassland ecosystems. The following findings showed that: Firstly, grassland degradation and improvement occurred simultaneously in Inner Mongolia. In the temporal scale, the NDVI of meadow steppe grasslands significantly degraded at a rate of -4.88×10-4 /a, while desert area NDVI increased at a rate of 1.98×10-4 /a. In the spatial scale, 23% of meadow steppe grassland areas experienced severe degradation, while 32% of desert steppe grassland areas significantly improved. Secondly, natural driving factors, especially climate-related factors, remained the primary driving forces for meadow steppe grasslands, typical grasslands, and desert steppe grasslands. Human activities also had significant impacts on relatively sensitive grassland desertification and desert areas. Thirdly, the contributions of topographical factors and livestock density to different types of grasslands have generally decreased, while soil moisture and temperature have increased. Temperature’s contribution has increased rapidly, and the contribution of precipitation exhibited periodic fluctuations. Other driving factors exhibited significant variations. Finally meteorological elements (temperature and precipitation) had a direct impact on grassland NDVI, while topographical factors and human activities generally exerted their influence on grassland NDVI through intermediary effects. This study aspires to provide targeted guidance for the conservation of Inner Mongolian grasslands, emphasizing the need to strike a balance between grassland preservation and livestock management, thereby ensuring the sustainable development of grassland ecosystems.