The agro-pastoral transitional zone in north China is located in arid and semi-arid areas.The ecosystem is fragile and sensitive to climate changes.Grassland is the main type of ecosystem in this region. Under the influence of climate change and human activities,grassland is prone to degradation.How to distinguish climate change and impact of human activities on grassland productivity needs to be further studied. CASA model and Thornthwaite memorial model were used here to simulate actual net primary productivity (NPP)and potential NPP of grassland from 2000-2015.Difference between potential NPP and actual NPP in grassland was found to represent the effect of human activities.42.29% of grassland was found to be in a degraded state from 2000-2015,57.71%of grassland was in a restored state,18.46%and 7.39%of grassland were degraded due to climate change and grazing(human activities)respectively.Under impacts of climate change and human activities and a combination of both,7.51%,30.26%and 19.94% of grassland were in a restored state respectively.Therefore,climate change is the main driver of NPP changes in degraded grassland, and ecological restoration policy is the main driver of NPP changes in restored grassland from 2000-2015.