Net primary productivity(NPP)is one of the key areas in research on regional carbon budget and climate change.Based on NPP,vegetation type maps and meteorological data(air temperature and precipitation), evolution of spatio-temporal patterns of NPP,and driving factors in Horqin region from 2000to 2010were analyzed using trend analysis,partial correlation analysis,and regression analysis.The results showed that the average annual NPP of Horqin region from 2000to 2010was 121.32g·(m~2·a)~(-1),and increased at a rate of 0.53g·(m~2·a)~(-1) in an area covering 48.77%of the region.The areas in which NPP increased were mainly located in Horqin district[7.46g·(m~2·a)~(-1)]and Kulun[5.09g·(m~2·a)~(-1)],and areas with decreasing NPP were mainly located in Balinzuo[-4.64g·(m~2·a)~(-1)]and Balinyou [-3.53g·(m~2·a)~(-1)].Vegetation types differ significantly in their carbon fixation ability.The carbon sequestration capacity of broad-leaved forests is the highest,followed by that of cultivated vegetation,and the lowest in shrublands.The effect of precipitation on NPP was stronger than that of air temperature,and the synergistic effect of precipitation and air temperature on NPP changes were stronger than those of each single factor.The synergistic effect of air temperature and precipitation may explain the NPP of meadows,broad-leaved forests,steppe,cultivated vegetation, and shrub land,which were 94.70%,87.50%,85.80%,85.30%,76.30%,respectively.