Two model polygons in the Central Mongolia are considered for investigation of vegetation dynamics. They are located in rainless climatic zones — arid and semiarid. For the emphasized polygons plots of the NDVI temporal variation and NDVI maps of its multi-temporal values on the base of Landsat TM imagery are constructed. The full-scale landscape indication of the selected NDVI areas with different values with the step through 0.1 is conducted. This indication is supported by the analysis of vegetation to environmental groups for drought resistance. Almost the entire territory of the emphasized polygons vegetation digression during this period was traced. The analysis of the time variation of NDVI shows a decrease of its values. This indicates a trend xerophytization already sparse vegetation of Gobi. In the semiarid climatic zone a digression vegetation trend is directly related to heavy load on the pastures.