As the largest freshwater Lake in China, Poyang Lake plays an important role in regulating the water level of Yangtze River and maintaining the ecological balance of surrounding areas. Therefore, this study utilizes Google Earth Engine (GEE) geospatial technology to acquire 124 remotely sensed images to explore the spatial and temporal changes of the four seasons of Poyang Lake from 1987 to 2019. The official statistics from relevant cities are used to quantitatively reveal the main driving factors of water body changes in Poyang Lake. Temporally, the water body area of Poyang Lake shows an obvious downward trend in general. Spatially, the water body area of Poyang Lake shows a gradual decrease from the center of the lake to the surroundings. In 1987-1998, the water body area of Poyang Lake showed an increasing trend, with an increase of about 727.90km². From 1998 to 2006, the water body area of Poyang Lake mainly showed a decreasing trend, with a decrease of 401.58km². The water body area of Poyang Lake increased slowly during 2006-2017. Anthropogenic factors and natural factors have influenced the changes in water body area of Poyang Lake to a certain extent. This study can provide valuable supporting data for the comprehensive environmental management and flood hazard monitoring of Poyang Lake.