The surface water resources in the Dongting Lake Basin play an important role in maintaining ecosystems, protecting biodiversity, and regulating the climate, but they are vulnerable to the impacts of climate change and human activities. Although extensive studies have been conducted on the dynamic changes in the surface water area of the Dongting Lake Basin, most of the existing research results lack long-term and whole-basin analyses. Moreover, the driving mechanisms are mainly based on qualitative descriptions, and spatial analyses are also limited to the main lake area. Based on this, this study aims to reveal the spatiotemporal evolution patterns of the surface water area in the entire Dongting Lake Basin and its sub-basins, clarify the contributions of climatic factors and human activities to the dynamics of surface water, and explore the migration patterns of the centroid of surface water distribution in the sub-basins. By comprehensively utilizing multi-source remote sensing satellite data and the JRC Global Surface Water Dataset products, and adopting methods such as the Mann-Kendall test, Pettitt test, Pearson correlation test, and centroid analysis model, this study analyzes and obtains the spatiotemporal variation patterns and main driving factors of the surface water area in the Dongting Lake Basin from 1990 to 2021. The results show that:①Over the past 30 years, the surface water area of the Dongting Lake Basin has shown an increasing trend, with the Yuanjiang River system being the most significant and it has increased by 420.07%, showing obvious spatial differences, and presenting a three-stage characteristic of "rapid expansion - fluctuating reduction - recovery growth" in terms of time;②The centroid of the surface water distribution in the Dongting Lake Basin has shifted southwestward overall, and the fluctuation range is mainly reflected in the east-west displacement, with a displacement of 19.56 km. The centroid migration of each sub-basin is directly related to the spatial characteristics of regional water conservancy project construction and ecological restoration, reflecting the remodeling effect of human activities on the spatial pattern of surface water;③Precipitation is the main climatic factor causing the increase in the surface water area of the Dongting Lake Basin, while human engineering regulation and ecological restoration measures such as water conservancy project construction and "returning farmland to lakes" have significantly changed the spatial distribution pattern of surface water in the basin;④Climate change contributes approximately 40%-55% to the changes in the surface water area of the Dongting Lake Basin, while human engineering regulation and ecological restoration measures such as water conservancy project construction and "returning farmland to lakes" not only significantly change the spatial distribution pattern of surface water in the basin, but also have a contribution degree of 45%-60%, becoming the dominant driving force. This study will help understand the long-term variation patterns of surface water resources in the Dongting Lake Basin and is of great significance for formulating scientific and reasonable ecosystem protection and restoration measures.