Saucer-shaped lakes within the Poyang Lake wetlands are regions with the largest vegetation biomass and the richest species diversity, supporting over 80% of the overwintering migratory birds of the entire wetland. These sub-lakes play a crucial role in maintaining the integrity of the wetland ecosystem and preserving species diversity. A comprehensive understanding of the distribution characteristics of the saucer-shaped lakes in the Poyang Lake floodplain is of great significance for the optimal allocation of regional water resources and the health of the wetland ecosystem. Supported by Google Earth Engine cloud platform, this study constructs a refined spatial catalog database of saucer-shaped lakes in Poyang Lake floodplain by integrating high-resolution, multi-temporal Sentinel-2A/B satellite imagery and multi-source auxiliary data to employ geospatial big data techniques. Based on this database, the study first systematically elucidates the true number, size, and spatial distribution patterns of these sub-lakes, and then explores the causes of the spatial distribution patterns and the major challenges faced by the saucer-shaped lakes in Poyang Lake wetlands. The results show that the Poyang Lake floodplain contains 319 saucer-shaped lakes larger than 0.01 km2, with a total area of 557.68 km2, accounting for approximately 28.88% of the annual average area of Poyang Lake area. Among them, lakes ranging from 0.01 to 1 km2 are the most widely distributed, constituting about 70.85% of the total saucer-shaped lakes. As the area of graded patches increases, the number of saucer-shaped lakes gradually decreases following a power function pattern. Regionally, the Gan-Fu estuarine delta contributes the most to the total area of saucer-shaped lakes, with 242.82 km2 (43.54%), followed by the Xiushui and Raohe River deltas, with 149.67 km2 (26.84%) and 138.62 km2 (24.86%) respectively. The southern lake-type water body zone (Zone II) has the smallest share of saucer-shaped lakes, accounting for only 4.76%, due to its location within the main navigation channel. Overall, the saucer-shaped lakes in the floodplain exhibit a "one main core, two secondary cores, and multi-centers" clustered spatial aggregation pattern, with spatial density evolving from high-density cores spreading outward in concentric zones. The spatial heterogeneity characteristics is marked by a "densely packed southwest, sparsely packed northeast" distribution. As the elevation of the lake-bottom increases, the number and area of saucer-shaped lakes show a trend of initial growth followed by a sharp decline, with a significant distribution dominance in the 12～14 meter elevation range. Under the influence of seasonal flood pulses, the scale and distribution of saucer-shaped lakes in the Poyang Lake floodplain are the result of the combined effects of regional topography, hydrological processes, and human activities. This study provides high-quality data support for research on hydrological process changes and their ecological impacts in Poyang Lake wetlands, and is expected to enhance the scientific basis for water resource management and drought early warning during the dry season in Poyang Lake.