Net primary productivity(NPP) is a material basis of ecosystem services. NPP plays a key role in the eco-security assessment and ecological risk assessment. The data of SPORT-NDVI, meteorology and landuse from 2000 to 2010 were used to estimate the temporal variation and spatial distribution of the NPP in Southern Shaanxi Province with improved CASA model. Results indicated that the annual average NPP of various landuse types all showed an upward trend from 2000 to 2010. The land-use types, in order of decreasing NPP, were forestland, shrub land, grassland, cultivated land and other types. During the years, the NPP of various landuse types increased in February and reached a peak in July. The NPP significantly declined in November and the minimum value appeared in following January. For the spatial distribution, the annual average NPP increased significantly in western Hanzhong City and the eastern and western regions of Shangluo City, increased steadily in the center of Hanzhong City and the most parts of central Ankang City, declined obviously at the juncture of Chenggu and Xixiang Counties, but did not change obviously in other regions of Southern Shaanxi Province. The NPP differences between monthly and annual change trends were apparent.