The lakeshore and the area around the lake were the key areas for lake ecological functions. The construction of lake ecological buffer zone was an important means to improve ecosystem services and lake ecological conservation. Lake Dianchi is located in the south of the main urban area of Kunming, Yunnan Province, with an altitude of 1886m and an area of about 300km². It is the largest plateau freshwater lake in China and plays an important role in supporting the ecological security barrier in Southwest China. Dianchi Lake Basin is the most concentrated and dynamic area of social economy and urban development in Yunnan Province as well. In recent years, with the rapid development of Dianchi Lake Basin, various ecological and environmental problems have arisen constantly. Based on the pollutant generation of land patches, the value equivalent factor per unit area and GIS analysis, this paper took Lake Dianchi as an example to identify the lake ecological buffer zone and evaluate the ecosystem service value around the lake. The results showed that:① the ecological buffer zone identification of Lake Dianchi delineated five types:mountain buffer zone, farmland buffer zone, village buffer zone, urban buffer zone and wetland buffer zone. The upper and lower border lengths were 171.50km and 127.55km, with an average width of 349.49 m and a total area of 38.12km². Among them, the wetland buffer zone was dominant and its width ranged from 20 to 825 m, with an area of 10.31km², accounting for 27.05%. ② The overall ecosystem service value of the Lake Dianchi region from 2000 to 2020 has been declining, the total value decreased from 1.240 billion yuan to 778 million yuan. The value grades were mainly low-grade and medium-grade, and the multi-period assessments showed that the proportions of the low-grade and medium-grade were 70.21% and 77.66%, respectively. The decreases of the ecosystem services value in the north coast of Waihai and Caohai were the most significant, reflecting the impact of intensive human activities such as urban construction. ③ The three scenarios of wetland, woodland, and grassland around Lake Dianchi increased the ecosystem service value by 58.87%, 21.08%, and 17.48%. Under the wetland scenario, the hydrological regulation, biodiversity and other indicators had a significant improvement effect. The research results showed the ecological value of the ecological buffer zone, and provided a reference for the ecological buffer zone construction of Lake Dianchi and ecological restoration.