Abstract: Satellite altimetry enables non-contact，large-scale Earth observation，providing technical support for monitoring changes in water levels of lakes where there is a lack of ground-based hydrological stations. The ICESat-2 laser altimeter features small footprints and high measurement accuracy，enjoying advantages in monitoring small-to medium-sized lakes. Therefore，this study extracted water level data from October 2018 to August 2022 for 1248 lakes across China based on ICESat-2 ATL08 data. The extracted data were validated using measured water level data from 18 lakes and Hydroweb data from 36 ones. Subsequently，based on the division of China's five major lake regions，this study analyzed variations in water levels of 957 lakes that were observed for over two years in at least four campaigns. The results show that the root mean square errors （RMSEs） between ICESat-2-derived and measured lake levels showed a minimum of 0.097 m. The cross-validation with Hydroweb data yielded a correlation coefficient of 0.95 and a minimum RMSE of 0.085 m. These results demonstrate the high precision and accuracy of the water level retrieval based on the ICESat-2 data. The lake levels on the Tibetan Plateau exhibited a slow rising trend，while those in northwestern China showed a declining trend. In eastern China，the water levels of large lakes displayed no significant variation trend，whereas those of small lakes showed pronounced fluctuations. Overall，the lake levels across China exhibited a gently rising trend. This study achieved high-precision measurement and monitoring of variations in lake levels across China，providing a scientific basis for water resource protection，ecological management，and the exploration of the responses of lake levels to human activities and climate change.