In order to evaluate the implementation effect of the Grain for Green Project (conversion of degraded farmland into forest or grass Land) and the eco-environment variation of Yulin, MODIS NDVI data was used to examine the spatial and temporal change of vegetation cover by applying maximum value composite (MVC) method based on the GIS. NDVI was higher in hilly loess region than that in blown sand region from 2000 to 2014. In general, the vegetation had improved during the past 15 years. In whole Yulin, the area of the improved vegetation accounted for90.7%, the area of degradation constituted only 1.0%, and the area of no variation was 8.3%. In hilly loess region, the area of improved vegetation accounted for 94.2%, mainly with moderate improvement. The area of vegetation improvement on slopes accounted for more than 80%. The obvious improvement at 7°-35° slopes constituted more than 51%. Therefore, the effect of the Grain for Green Project was obvious.