Abstract: Maintaining ecological health in Dongting Lake area is of great significance to regional sustainable development. However, with the disordered expansion of urban space, ecological security is facing a great threat. Based on the expansion rate index, expansion intensity index and remote sensing ecological index (RSEI), this paper analyzed the spatio-temporal changes of urban space and eco-environmental quality in Dongting Lake area from 2010 to 2020, and explored the impact of urban space evolution on eco-environmental quality through exponential regression model. The results show that:(1) From 2010 to 2020, the urban space in Dongting Lake area has accelerated expansion, with the urban area increasing by 232.7km², concentrated in the area around Dongting lake, presenting a multi-point agglomeration state and continuously expanding to the surrounding areas. (2) The ecological environment quality in Dongting Lake area fluctuated and showed a trend of improvement. The areas with medium, general and poor ecological environment quality spread to the surrounding areas. (3) During the study period, eco-environmental quality was negatively correlated with urban spatial expansion intensity. The above research findings can provide a better reference for the coordination and optimization of urban development and ecological protection, in order to provide support for the high-quality development and sustainable development of Dongting Lake area and other lake area.