Abstract: Based on the MSS data in the 1970s, TM data in the 1990s and ETM data at the beginning of the 21st century in the Qiangtang Nature Reserve in Tibet, in this paper the area and spatiotemporal variation of the lakes larger than 1 km² in the nature reserve were interpret with remote sensing analysis. The results show that the lakes in the Qiangtang Nature Reserve were in a shrinkage during the period from 1975 to 1990, their number was decreased from 388 to 277, their total area was reduced from 6 603.3 km² to 5 539.7 km² (reduced by 16.1%), but thereafter until 2000, area of the lakes was enlarged dramatically. Number of the lakes was increased by 164 and to 441, total area of the lakes was enlarged to 9 652.2 km² and by 4 112.5 km² (enlarged by 74.2%) compared with that in 1990. Regionally, change of the lakes in the east was significantly higher than that in the west. The average daily and monthly temperature, average monthly maximum and minimum temperature, monthly precipitation and evaporation at 6 meteorological stations including Shiquanhe, Gaize, Bange, Shenza, Naqu and Anduo were analyzed, and the results revealed that the temperature at the 6 stations was increased; precipitation was significantly increased in the east, and its change was not significant in the west; annual evaporation was in a decrease trend. It is considered that precipitation was the most important factor affecting the change of the lakes, and then temperature and evaporation.

Key words: lake area, climate change, Qiangtang Nature Reserve, Qinghai-Tibet Plateau