The buffer zone is an indispensable part of the lake ecosystem. Study on land use changes and ecosystem service value (ESV) in the buffer zone is important to maintain the water security and biodiversity of the lake. Based on seven Landsat remote sensing satellite images from 1988 to 2018, this study adopts Land use correlation analysis method and ESV equivalent factor estimate method to deeply analyze spatiotemporal changes of land use and ESV changes in the buffer zone of Poyang Lake in last 30 years. The results show that:(1) the land use type of the buffer zone of Poyang Lake has gradually formed a pattern in which the cultivated land was dominant and the proportion of major land types such as forestland, grass land, water area and construction land were relatively balanced. During this period, the cultivated land area increased significantly, with an increase of 21.48%. The area of construction land and forestland increased by 542.90% and 326.23%, respectively; the cultivated land, water area and grassland were the main sources of their area increase. Grass land area showed a significant decrease of 66.79%, which was mainly transformed into forestland, cultivated land and water area. Water area and unused land decreased slightly. In the study area, the dynamic degree of comprehensive land use in Nanchang County was 1.81%, which was higher than that in other 11 districts and counties, showing that Nanchang County witnessed a bigger change in land use. (2) In recent 30 years, the ecosystem service value in the buffer zone of Poyang Lake generally showed a trend of increase first and then decrease, with a total loss of 2.554 billion yuan and a total decrease of 24.18%. At the same time, changes in different types of ESV were similar to that of land use. Hydrological regulation, which plays a vital role in ecological service function in study area, occupied 66.03% of the total ESV. (3) Water area and grass land contributed the most to ESV changes and were the main influencing factors of ESV changes in the buffer zone of Poyang Lake. The decrease of water area mainly explains the decline of ESV in the buffer zone. In general, restoration and protection of water area and grass land in the buffer zone of Poyang Lake is of great significance in maintaining the biodiversity and service function of its own ecosystem, and is also crucial for protecting the ecological environment of the surrounding area and even the middle and lower reaches of the Yangtze River.