Abstract: Based on the remote sensing images in 1992 and 2002 and the MODIS images in 2001 and 2005, as well as relevant statistical information, the integrated characteristics and the spatial heterogeneity of land use change in Mongolia were analyzed, with the driving factors discussed. The results showed that from 1992 to 2005, the area of farmland and forestland in Mongolia decreased significantly, that of construction land and unused land exhibited an increasing trend, water area showed a slight decrease, and grassland had less change in its area but declined in its quality. A significant regional difference was observed in the land use change, which mainly concentrated in the mountain areas of the western plateau and in the northern part of southern Gobi area. Both natural (climate change and natural disasters) and social (policies, regulations, and population increase) driving factors were responsible for the land use change in Mongolia.

Key words: watershed, water quality, ecological health assessment, environment protection.