As a result of energy and material exchange at the lake-atmosphere interface, the variations of lake ice phenology are of great significance for indicating regional climate change and lake response process. Based on the boundary data of Selin Co, some multi-source remote sensing (RS) datasets including Terra MODIS and Landsat TM/ETM+/OLI product, combined with meteorological records and lake data to analyze spatiotemporal variations of ice phenology of Selin Co and its relationship with climate factors and physical and chemical factors between 2000 and 2020 by applying both RS and GIS technology. The main research conclusions are as follows:(1) Freeze-up start (FUS) and freeze-up end (FUE) of lake ice appears in late November-early December, and late December-early January, respectively. The duration of lake ice freeze-up is about a month. The time of break-up start (BUS) and break-up end (BUE) of lake ice appears in late March-early April, and late April, respectively. The duration of lake ice break-up is about half a month. (2) Data show that FUS dates of lake ice have been delayed at a rate of 11.3 d/10 a from 2000 to 2020. FUD (freeze-up duration) time of lake ice showed an increasingly shortening trend. Ice cover duration had been shortened at a rate of 13.5 d/10 a. (3) Selin Co can be characterized by opposite spatial patterns in both freeze-up and break-up processes. Lake ice freezes from the northern and eastern lakeshore and gradually expands to the center of lake. Instead, lake ice break-up begins in the center of the lake. (4) Ice phenology of Selin Co is influenced by climate and physico-chemical factors of the lake itself. The average temperature of winter half-year (between November and the following April) plays a dominant role in ice phenology variations of Selin Co. Wind speed and precipitation both also some influences on the formation and melting of lake ice cover and also cannot be neglected. In the recent 20 years, with the expansion of Selin Co area, the increase of turbidity and the decrease of water clarity, the freezing dates of lake ice were gradually delayed. Under the background of global warming, the area expansion of lakes on the Tibetan Plateau, including Selin Co, has accelerated. The results of this study can provide a reference for understanding the climate indicator significance of lake ice phenology information and the feedback process of lakes under the changing environment.