In order to analyze the annual,monthly and spatial characteristics of arid lake extent change under the impacts of climate change and human activities,Chaiwopu lake of Urumqi is selected as an example to map the lake area change and level change with time-series Corona and Landsat imagery in the last 50 years,and its lake level changes from 2003 to 2009 are also delineated with ICESat/GLAS altimetry data. The results showed that,Chaiwopu lake changes are presented as 3 stages: 1964-2004,2005-2010 and 2011-2014,and the annual area changing rate are-0.012 km~2·a~ (-1),- 0.256 km~2·a~ (-1) and-4.798 km~2·a~ (-1),respectively. The overall lake area shrinking mode is from gentle to significant,and the lake water was firstly found dry up on September 25~(th),2014,and its ecological function is weaker and weaker. The seasonal characteristic of Chaiwopu lake extent changes are showed as,lake water extent reach its peak in spring and touch its valley in autumn,and the seasonal change becomes more obvious when the drastic water area change happened after 2005.Monthly lake area curves showed that Chaiwopu lake is losing its area rapidly year by year. When it comes to lake water level and spatial boundary,their change matches well with the Chaiwopu lake basin topography,which is represented as"rock-ribbed shore and flat bottom". Before 2005,water area change was insignificant while lake water level was significant when lake water volume is decreasing. After 2005,lake water boundaries were shrinking. When they are shrinking to the lake bottom in 2012,the underground water level has high correlations with water area change. In the wet years between1999 and 2004,lake shrinking rate is decreasing and Chaiwopu lake keep its dynamic water balance during that period. Exceeding groundwater exploitation after 1993 is the main reason of lake extinction,leading to ecological disaster in this region.