Based on Landsat TM/ETM+/OLI remote sensing images in the arid region of Northwest China in 1990,1999,2007 and 2015,104 data of lakes with area greater than 1 km~2 were obtained by Normalized Difference Water Index(NDWI)and the driving mechanism of lake change was analyzed.The results show that:(1)From 1990 to 2015,the lake area in northwestern arid region was increasing,and the area of lake in 1999~2007 was the most obvious;(2)In the northwest arid region,the whole lakes showed an expanding trend,but there were obvious regional differences.The area of the lakes decreased first and then increased, and the lakes were the largest and the most widely distributed.Area of the lake continued to reduce the number of small,was distributed in the hinterland of Tengger Desert;(3)Precipitation and temperature are two important factors influencing lake change.The change of lake area is consistent with precipitation,temperature and evaporation,and the impact of human activities on the change of lake area is insignificant. While the change of plain lake area is affected by natural factors and human activities.Desert lake area is the result of climate change and groundwater recharge source changes.The results promote to improve the temporal and spatial characteristics of the lakes in Northwest China,And provide a reasonable basis for the study of lake change and environmental protection in this area.