Based on a pixel scale linear regression model, we extended Advanced Very High Resolution Radiometer Global Inventory Modeling and Mapping Studies (AVHRR GIMMS) using MODIS normalized difference vegetation index (NDVI) data and constructed a time series of NDVI covering Xinjiang province from 1982 to 2013. We also analyzed the spatial-temporal changes in vegetation growth in different districts and correlated these changes with climate factors. NDVI increased significantly in the plain regions of northern and southern Xinjiang and in the mountainous region of southern Xinjiang, but decreased in the mountainous region of northern Xinjiang. Rainfall and minimum temperature were important factors in vegetation growth in Xinjiang. Vegetation was influenced by rainfall on the northern Xinjiang plain; crop growth was influenced by temperature, especially minimum temperature. On the southern plain vegetation growth was influenced by both rainfall and temperature and in the mountain regions by rainfall. Rainfall played a more important role in grassland compared to forest and cropland areas; rainfall has little influence on cropland because of the use of irrigation. Increasing rainfall and temperature promoted an increase in the NDVI while the degradation of vegetation in mountainous region of northern Xinjiang is influenced by a range of factors including climate change, fire, and the control of grazing pressure by fencing.