To counteract the detrimental impacts of vegetation degradation, the Chinese authorities have initiated numerous ecological restoration projects (ERPs) in Inner Mongolia (IM) since the 1990s. However, the medium- and long-term consequences of these ERPs on vegetation dynamics remain uncertain. This study employed net primary production (NPP) as an indicator to quantify the independent contribution of climate change, management measures and land conversion to vegetation dynamics through scenario modeling over four six-year periods (2001-2006, 2006-2011, 2011-2016, 2016-2021). The findings of the study indicated that human activities were the main driver of changes in NPP in Inner Mongolia across all three six-year periods (2006-2011, 2011-2016 and 2016-2021), with the exception of the period from 2001 to 2006,during which climate change was identified as the dominant factor in this period. The primary variables influencing the net primary production (NPP) of diverse vegetation types, including grassland, crops, and forests, have undergone notable shifts over time. Nevertheless, human activities have consistently been the primary driver of NPP changes in desert ecosystems. During the study period, the observed increase in NPP of IM vegetation was primarily attributable to the implementation of management measures in human activities. This phenomenon was observed consistently across the three main vegetation classes: grassland, forest and desert. In contrast, land conversion was identified as the primary driver of the increase in NPP in cropland during the periods 2001-2006 and 2011-2016. This understanding is crucial for the development of more effective policies and measures for ecological restoration.