The 33 years (from 1981 to 2013) vegetation fractions were estimated based on NOAA/HAVRR NDVI and MODIS NDVI data in Xilingol steppe. Variations in grassland degradation were quantified according to the national standards of grassland degradation, the driver factors were analyzed as well. The results indicated that the grassland was in a degradation trend in studying period. However, the degradation states are different before and after the year of 2000. Before 2000 the degradation was in deterioration, but between 2000 and 2005 degradation changed. The grassland in the middle and eastern of Xilingol steppe improved, on the contrary the western was worse. After 2005 the whole area grassland was getting better, especially between 2010 and 2013. Degradation area was shrinking, and the degraded grassland was dominated by moderate and mild degraded grassland. The stocking number and grassland reclamation of farming activities and population quantity were the main factors of grassland degradation in Xilingol steppe. Summer precipitation and average temperature were other important factors to intensify grassland degradation. Meanwhile unreasonably mining of energy and mineral resources were other important factors to cause grassland degradation.