Abstract: Xinjiang is located in the hinterland of arid areas in the northwest China. Due to the hot summer and low precipitation，water shortage is an extremely serious problem in the region. Lake as an important water carrier in the arid region maintains the balance of the fragile eco-system and plays a vital role in the social-economic development. Therefore，the lake changes and the driving factors were widely concerned. By using “3S” （RS，GIS，GPS）technology and based on the research unit of catchment，this study investigated the changes of the lakes in the region over the period from 1975 to 2010. The paper selected MSS data in 1975，ETM data in 2000 and TM data in 2010 and extracted information of a single lake with an area greater than 0.25 km2 by using man-computer interactive interpretation method. The results showed that there were a large number of lakes distributed over the region but most of them were small scale lakes. The natural lakes were the dominant in the region. The Junggar Endorheic System had the largest lake area while the Tarim Endorheic System had the largest number of lakes. Overall，the number of the lakes and the area of the lakes both increased in the period from 1975 to 2000 and then both decreased in the next 10 years to 2010. There was an obvious difference between the natural lakes and the artificial lakes on the numbers and the areas. The number and the area of the artificial lakes in the region both kept increase over the study period which was different with the natural lakes. The lake areas increased in all catchments in Xinjiang from 1975 to 2000. However，the lake areas significantly decreased except the lakes in Ili River catchment. The precipitation and the temperature were the main climatic factors impacting the changes of the lakes. Human activities significantly influenced the changes and the trends of the lakes，which caused the differentiation in the lake changes between the natural and the artificial lakes. This study provided theoretical support to the water resources management and utilization on catchment unit.

Key words: arid regions, lake, remote sensing, changes, Xinjiang