The aquatic-terrestrial ecotone is a typically transitional geographic space, carrying a special and complex relationship between human and land. As the research progresses, the aquatic-terrestrial ecotone has become one of the major concerns affecting human-land relationship. According to the overwater, throughput and seasonal characteristics of Poyang Lake, the integrity of administrative division and scale effect are considered. Based on high-resolution remote sensing images and long time series water level change data, unsupervised classification, visual interpretation and survey verification are used. Delineating the geographical scope of the aquatic-terrestrial ecotone of Poyang Lake in two dimensions, natural and administrative divisions, and elaborating its basic characteristics, such as natural, economic and social. The theoretical basis, practical significance and scientific content were analyzed. The result shows that:(1) the maximum natural range of aquatic-terrestrial ecotone of Poyang Lake is 2508.08 km². As the water level changes, its range also changes. The administrative range involves 78 township units in 11 counties (cities and districts), including 974 administrative villages; among them, 40 are in Jiujiang City, 20 are in Nanchang City, and 18 are in Shangrao City. (2) The landscape elements are varied, such as water bodies, grass beaches, soft mud, hard mud, and sandy beaches. The economic development is mainly based on ecological agriculture and ecological tourism, and the population distribution shows band features, which is highly consistent with the range of ecotone. From county scale, the population density of Lushan City, Duchang County, Poyang County and the newly built districts is relatively high. (3) The natural basis, scale effect and connotation characteristics are the theoretical basis of the scope division. The theories include aquatic and terrestrial ecosystems, territorial systems of human-land relationship, and the coupling of nature and society. It is important to explore the process, mechanism and law of human-environment interaction. (4) Further research can be carried out in terms of landscape pattern changes and social life changes to reveal the special human-land relationship changes in this region. For instance, the impact of landscape pattern changes on human production and life, animal and plant habitats can be further simulated and investigated under different conditions. Also, future work can focus on the changes of human-land relationships at different stages to find out the main driving factors for optimal control. This research is a supplement to the previous division of aquatic-terrestrial ecotone, and it also provides a new idea and reference for the division of this type of aquatic-terrestrial ecotone.