Climate change, increased CO₂ concentration, nitrogen deposition and land use change are currently recognized as the main factors affecting the structure and function of ecosystems. Among them, the research on the influence of nitrogen deposition on carbon cycling process is still insufficient with great uncertainty. In recent years, as the productivity of grassland ecosystem is reduced due to long-term intensive grazing, nitrogen has become a limiting factor of typical grassland. The increasing rate of nitrogen deposition in Asia is probably higher than the global average as reported by previous research. In view of this, it is of significant importance to study the effect of atmospheric nitrogen deposition on grassland ecosystem in Central Asia. In this study, Denitrification-Decomposition (DNDC) model was utilized to analyze the temporal and spatial variation of grassland net primary productivity (NPP) in Central Asia from 1979 to 2014, to explore the effects of nitrogen deposition on grassland NPP. The results showed that:(1) During 1979-2014, the annual averaged temperature in Central Asia showed a significant increase trend((0.03±0.01)℃ a^-1, R²=0.40), while the precipitation decreased with the trend of (2.26±1.78)mm a^-1(R²=0.35). (2) from 1979 to 2014, the average NPP of grassland in Central Asia was about(173.10±31.80)g C m^-2 a^-1, and the spatial and temporal differences of grassland NPP were obvious. The highest NPP of grassland was found in forest meadow, followed by temperate grassland, and desert grassland NPP. Moreover, the grassland NPP increased at the rate of(2.67±1.30)g C m^-2 a^-1. (3) The current nitrogen deposition scenario generally benefits the growth of grassland NPP in central Asia, which increases the grassland NPP by 0.42 Pg C in the last 36 years. Based on the existing studies, we cannot determine whether the decrease of NPP in this part of grassland is caused by reaching the critical load of nitrogen, and more in-depth studies are needed.