Abstract: The paper aims to scientifically evaluate the vegetation productivity and implement relevant ecological projects of reforestation in northern Shaanxi. A quantitative analysis was carried out on the temporal and spatial distribution and variation characteristics of NPP and their relationships with the climate factors and human activity in this area, based on 2000-2013 annual net primary productivity (NPP) data from MOD17A3 dataset and land use classification data and meteorological data. The results showed that: in the study area, the annual NPP ranged from 150 gC/(m²·a) to 300 gC/(m²·a) during 2000-2013, with an average of 134.23 gC/(m²·a); the average annual NPP was higher in the south and lower in the north. The overall annual NPP showed an increasing trend in the study area except that with zero vegetation coverage. The correlation of NPP with climate factors showed both positive and negative side, a majority of which was found to have a significantly positive correlation with precipitation, but the correlation with average temperature was less significant. A tiny part of NPP passed the test of significance (α＜0.05) in both correlation studies. The land cover change dramatically impacted vegetation NPP evolution, which suggested that closing hill for forestation and restoring farmland into forestland improved the vegetation.