Abstract: The water surface mapping of the nine plateau lakes in Yunnan Province from 1988 to 2018 was carried out by using the Google Earth Engine(GEE)cloud platform with long-term Landsat images.Meanwhile, the temporal and spatial variation of the water surface areas of the nine plateau lakes and its driving factors were analyzed.The results showed that:(1) In the past 30 years, the water surface area of the nine plateau lakes decreased by 23.93 km2 from 1 024.91 km2 in 1988 to 1 000.98 km2 in 2018,revealing an overall trend of “increasing followed by decreasing”.(2) The water surface areas of most plateau lakes remained stable, however, a few lakes showed significant changes.For example, the areas of Qilu Lake and Yilong Lake shrank significantly after 2008.(3) Analysis shows that from 2013 to 2017,the correlation between the change of water surface areas and precipitation is strong(R=0.9,p=0.08),while it is negatively correlated with air temperature(R=-0.63,p=0.08)from 1998 to 2018.The government′s economic development and lake protection policies and the changes of land cover/use are the most important human factors that cause changes of water surface areas of the nine plateau lakes.In conclusion, the dynamic changes of the nine plateau lakes in Yunnan Province are caused by climate changes and human activities jointly.