In order to reveal the spatio-temporal dynamics of different types grassland net primary productivity(NPP)in Inner Mongolia,and explore the correlation between NPP and climate factors,based on remote sensing data,meteorological data and grassland classification data of China in the 1980sand CASA model,grassland NPP in Inner Mongolia from 2001to 2016was simulated,and the spatial and temporal dynamics of NPP in different grasslands and its response to climate factors were analyzed.The results showed that:(1)From 2001 to 2016,the mean annual NPP of grassland in Inner Mongolia was 163.9gC/(m~2·a),which was higher in the northeast and lower in the southwest.The total annual NPP was 31.6TgC a-1(1Tg=1012g),(2)In the past 16years,the mean annual NPP of grassland in Inner Mongolia showed an increasing trend,with a growth rate of 2.1gC/(m~2·a),and the annual fluctuation was large,(3)The mean annual NPP of temperate meadow grassland, thermal grassland,lowland meadow,mountainous meadow and swamp increased significantly,while the other five types decreased,(4)The correlation coefficients of NPP with mean annual temperature and total annual precipitation are-0.01and 0.4,respectively and(5)Except for the temperate desert steppe and the temperate steppe desert,the NPP of other grasslands was negatively correlated with temperature,and the NPP of all grasslands was positively correlated with precipitation.Precipitation was the most important hydrothermal factor affecting NPP in Inner Mongolia grassland.