Abstract: Siling Co, the largest lake in Xizang Autonomous Region, has expanded significantly in the past few years, threatening surrounding pastoral activities, infrastructures, and even the ecological environment. This study systematically reconstructed the time series of changes in the lake area, water level, and water volume of Siling Co from 1995 to 2023 using optical images from satellites Landsat and GF, as well as altimeter data from satellites ERS-2, ICEsat, Cryosat-2, and ICEsat-2. Through Mann-Kendall trend analysis, the study determined the stages of the lake area changes and revealed the key characteristics of various stages. Furthermore, it also made a preliminary judgement on the inundation trend and its impacts. The results indicate that from 1995 to 2023, Siling Co experienced an increase in water area of 676.75 km² (with an annual average of 24.17 km²/a), a water level rise of approximately 13.32 m (with an annual average of 0.48 m/a), and a water volume growth of 28.45 Gt (with an annual average of 1.02 Gt/a). The changes in Siling Co from 1995 to 2023 can be divided into four stages: the fluctuating growth stage from 1995 to 2000, the rapid expansion stage from 2000 to 2011, the relatively stable stage from 2011 to 2017, and the re-expansion stage from 2017 to 2023. The inundated areas during the fluctuating growth and rapid expansion stages were primarily concentrated in the northern and southern parts of the lake. During the relatively stable stage, no significant expansion was observed in the inundated areas. In the re-expansion stage, the inundated areas were distributed in the eastern part of the lake. The continuous rise in the water level of Siling Co led to an annually increasing risk of surrounding inundation. Currently, the areas exposed to a high inundation risk are primarily concentrated along the south bank of the lake, which should be the focus in future monitoring and research.