Abstract: A study was carried out on development of aeolian desertification in the valley of the middle reaches of Yarlung Zangbo River in the past 18 years(1990-2008) with the aid of RS and GIS technologies.It was found that the area of aeolian desertified lands in this region increased by 5 267 hm² from 1990 to 2008,and the total area of aeolian desertified land reached to 81 842 hm² in 2008.In the first 10 years(1990-2000),it increased by 3 085 hm² averaging by 308 hm² annually and in the next 8 years(2000-2008) by 2 182 hm²averaging by 273 hm² annually.Obviously,the rate slowed down in expansion in the late years.Wind erosion is the main driving factor of aeolian desertification in this region,and increased precipitation and large scaled afforestation in Xigaze and the southern section of the mountains beginning from 2000 are the main reasons for the slowed down aeolian desertification rate.