Abstract: The paper aims to evaluate the grassland protection policy in Gaize County. Using the 3S technology, MODIS-NDVI data, meteorological data and grazing prohibition data during 2000-2014, the authors investigated the spatial and temporal distribution of vegetation in Gaize County. The results showed that: the vegetation cover was generally sparse and the average NDVI ranged from 0 to 0.2 while the maximum composite NDVI was from 0.1 to 0.3. The vegetation cover in the south part of Gaize County was much better than that in the north part. Summer had the best vegetation cover and spring had the worst. The vegetation had no significant seasonal change in the Kunlun Mountains which was located in the north part of Gaize County. As a whole, the vegetation distribution was quite stable during 2000-2014 in Gaize County. The vegetation stable areas and the areas with improved vegetation cover accounted for 45.46% and 11.28% of the whole county area, respectively, the areas with worsening vegetation cover accounted for 8.69% of the county area. The area with better vegetation was larger than the area with worse vegetation. The variations of precipitation and temperature were not beneficial to the improvement of vegetation during 2008-2014, so the grassland protection policy played a significant role in vegetation amelioration.