Abstract: The evolvement of sandy desertified land in Horqin region for the last 5 decades was dynamically monitored and analyzed based on the grading indexes of desertified lands and the effective monitoring method.In the 20th Century,the desertified land developed at the most fast speed from late 1950s to middle 1970s and the total area had increased by 9 084 km²;the development of desertified land lasted its fast-developing trend from middle 1970s to late 1980s and the total area had increased by 9 624 km²;as entering 1990s the processes of desertification became inversed,the total area had decreased from 61 008 km² in year 1987 to 50 142 km² in year 2000 and had decreased by 10 866 km² during the 13 years.In the past 50 years the desertified land has generally experienced the processes of developing → further developing → inversing.Although the status of desertified land development was still arduous by year 2000,the revising trend is hopeful.If the trend of eco-environment being improved and the environmental caring capacity being heightened is going on the eco-environment and the social economy are possibly entering the sustainable development.

Key words: last 5 decades, Horqin region, desertified land, dynamic monitor