To explore the impact of climate change on the lake area of Selin Co,this paper used maximum likelihood method to extract the lake areas of Selin Co for the past 33 years (1988-2020) from Landsat data,then analyzed the variations in lake area,temperature,precipitation as well as snow cover depth in Selin Co basin using linear regression and Mann-Kendall test,and discussed the correlation between lake area and climate change by Pearson correlation.The results showed that,in the past 33 years,the Selin Co Lake expanded by 650.70 km² at the rate of 203.34 km²／(10 a),mostly at northward and southward directions.The average annual temperature and precipitation increased significantly at the rates of 0.50 ℃／(10 a) and 17.32 mm／(10 a) (p<0.05),while the average maximum snow cover depth decreased significantly at the rate of 0.65 cm／(10 a) (p<0.05) during 1988-2020.An extremely significant correlation was found between the change of lake area and the rise of air temperature in the basin as well as the decreasing maximum snow cover depth in cold season (p<0.001),indicating that the Selin Co lake's expansion in the past 33 years was a consequence of the increasing water supply from ice-snow meltwater due to the rising air temperature in Selin Co basin.