Glacial lakes of the Altay Mountains in China during the past 20 years were interpreted and classified based on the remote sensing images of Landsat TM(1992)/ETM+(2002)/ OLI(2013) respectively, with properties including basin, altitude and slope gained from SRTM DEM by spatial overlay analysis in GIS. The features of temporal-spatial distribution and variation of glacial lakes during 1992- 2013 and factors which impacted the evolution of glacial lakes in this area were discussed. The results indicate that: (1) there were 1147 glacial lakes in the Altay Mountains of China in 2013, with a total area of 101.628 km2, and both the number and area of glacial lakes increased during the past two decades. (2) The responses of ice-scour lakes and moraine-dammed lakes to climate change were totally different. (3) With temperature rising, the peak of profit and loss of ice-scour lakes reached a higher altitude, and the variation of moraine-dammed lakes became more unstable. (4) Westerly circulation had a significant influence on the glacial lakes, the precipitation on the west-facing slope was sufficient, therefore the west-facing ice-scour lakes varied little, while the west-facing moraine-dammed lakes kept expanding as the profit constantly overmatched the loss. (5) Owing to the lower elevation, glacial lakes in this region were sensitive to climate change than other alpine-plateau areas in western China over the past two decades, both surplus and deficit of water were of high quantity, resulting in few net increment after lake water balance. (6) The magnitude of temperature rise and precipitation reduction during 1992-2002 were larger compared with the period 2002-2013, and the quantity of water surplus and deficit of glacial lakes in spatial units of each size was greater compared with the 2002-2013 period. There is a positive correlation between water surplus and deficit of glacial lakes and the range of temperature rise and precipitation reduction.