Abstract: The changes of water resources and theirs influence on environment are key points for arid researches.This paper mainly focuses on the evolvement of Manas lake in Xinjiang,which is based on the remote sensing images from 1972 to 2004 integrated with measured topographical data in 1999 and other materials from 1950s.The results of this research show that(1) Manas lake is a part of old Manas lake group and it is not a migratory lake;(2)there are two periods of the lake evolvement in the past 50 years:from 1949 to 1999/2001 and from 1999/2001 to nowadays,which are respectively corresponding to negative and passive evolvement process of Manas lake;(3)the trend of Lake change is synchronous to the change of Manas river's runoff;and(4)the main driving forces for the lake evolvement in the past 50 years are human activities and climate change.