In this study, Landsat MSS images in 1975 and Landsat TM images in 2005 were used to monitor the development of land desertification in Zoige Basin with the assistance of RS and GIS techniques. The result shows that the area of desertification land increased by 2 105.36 km² in this region from 1975 to 2005, nearly at the rate of 70.18 km²/a. The increased desertification land is mainly of moderately and slightly desertified ones, and the area of which is 957.13 km² and 1 146.75 km² respectively, but severely desertified land just increased by 1.48 km². Annual mean temperature increased by 1.41℃ from 1965 to 2007. Meanwhile, annual mean precipitation decreased by 34 mm. At the same time, human activities, especially over-grazing, strongly disturbed the ecoenvironment of this region. Therefore, it can be concluded that the compound effect of natural and anthropogenic factors is the reason for the rapid development of desertification land in the basin.