We studied sandy desertification in five counties near Tibet′s Lhasa Airport, in the middle reaches of the Yarlung Zangbo River valley. We analyzed the spatial distribution of aeolian sandy land and its evolution since 1990 by interpreting Landsat data from 1990, 2000, and 2008 using geographic information system (GIS) technology. The results were then matched to a regional 1∶250 000 digital elevation model using the GIS software. The driving causes of aeolian sandy desertification were analyzed from the perspectives of climate change and human vegetation restoration activities to clearly define the current situation and to provide guidance for future vegetation restoration. The total area of aeolian sandy land in 2008 was 42 462.38 hm2, versus 41 440.61 hm2 in 1990 and 42 068.89 hm2 in 2000, representing a 2.5% increase from 1990 to 2008. The areas of aeolian sandy land caused by windblown sediments and wind erosion in 2008 totaled 33 088.87 hm2 and 9373.51 hm2, respectively, representing 77.9% and 22.1%. The area of aeolian sandy land totaled 14 200.54 hm2 within 20 km from Lhasa Airport and 10 351.03hm2 between 20 and 40 km from the airport. The aeolian sandy land mainly occurred at elevations from 3600 to 3800 m; sandy land at these elevations accounted for 77.9% of the total. The aeolian sandy land was mainly found in flat areas, which accounted for 45.4% of the total, versus 13.8% and 13.4% for southeast- and south-facing slopes, respectively. The area of aeolian sandy land has increased slowly throughout the study period, at a rate of 62.83 hm2/a in the first 10 years and 43.72 hm2/a in the last 9 years, representing a gradual slowing. However, the overall rate of expansion since 1990 averaged 53.78 hm2/a. The increased area of sandy land mainly resulted from the region′s harsh climate and fragile environment, combined with a warmer and drier climate that accelerated the desertification process. We obtained meteorological data from 1957 to 2007 from two monitoring stations in the study area (Lhasa and Zedang), and wind speed and direction data from 1980 to 2006 from the Lhasa Airport meteorological station. During this period, the study area has grown increasingly warm. The average rates of temperature increase from 1990 to 1999 and from 2000 to 2007 were 1.29 and 1.96℃ per decade, respectively. Both are much higher than the overall average of 0.34℃ per decade since 1957. The rainfall varied widely during the study period. The average rate of precipitation increase has been 5.56 mm per decade since 1957. The annual rainfall from 1957 to 2007 averaged 419.90 mm, versus averages of 437.20 mm from 1990 to 1999 and 474.06 mm from 2000 to 2007 (both above the long-term average). The annual mean wind speed from 1980 to 2006 averaged 2.08 m/s, versus averages of 1.90 m/s from 1990 to 1999 and 1.88 m/s from 2000 to 2007 (both below the long-term average). The air temperature increase therefore appears to be the main driving factor for the development and spread of aeolian sandy land. The slightly higher precipitation and lower wind speed in this region since 2000 were natural factors that slowed the expansion of aeolian sandy land during this period, and an increased area of forest plantations, combined with a declining area of bare riverbeds, also slowed this expansion, possibly by preventing or reducing sand transport from riverbeds and dunes to river banks and hillsides in the valley.