The MODIS data and the improved CASA model were used to estimate the vegetation net primary productivity (NPP) in the Ili River Basin from 2008 to 2018. The spatial and temporal differentiation characteristics of the Basin were analyzed by means of unary linear regression trend analysis, coefficient of variation, and Hurst index. The results are as follows:(1) In terms of temporal characteristics, the NPP of vegetation in the Ili River Basin fluctuated and increased. The annual NPP of vegetation in the Ili River Basin showed a single peak pattern. The relationship between the NPP of vegetation in four seasons in the Ili River Basin is as follows:summer > spring > autumn > winter.(2) In terms of spatial characteristics, the NPP of vegetation in the Ili River Basin was lower in the northeast and higher in the southwest, and was distributed in a circular pattern along the Tianshan Mountains. The NPP of each vegetation type was forestland (624.13 g C m^-2 a^-1) > cultivated land (575.04 g C m^-2 a^-1) > grassland (270.57 g C m^-2 a^-1) > bare land (114.26 g C m^-2 a^-1). The NPP of vegetation in the Basin showed different variation characteristics in altitude, longitude and latitude. (3) In terms of spatial stability, the NPP of vegetation in the Ili River Basin had obviously spatial differences. From large to small, the area proportion of variation degree was stable (44.78%) > unstable (25.47%) > relatively stable (16.46%) > very unstable (13.3%). (4) In terms of the future change trend, the NPP of vegetation in most areas of the Ili River Basin will continue to increase in the future, and the area proportion of the future change trend is continuous increase (51.67%) > from increase to decrease (31.75%) > continuous decrease (9%) > from decrease to increase (7.54%) > unpredictable (0.06%). The results can provide a reliable theoretical basis for the sustainable development of the ecological environment, society and economy in the Ili River Basin.