Abstract: As the highest spatial organization form of urban development, the urban agglomerations will inevitably have a coercive impact on the regional ecological environment in the process of high-speed urbanization. How to balance the ecological environment and urbanization development has become an issue worthy of attention. Based on the cloud platform of Google Earth Engine, the improved night light index and remote sensing ecological index are adopted respectively to characterize the level of urbanization and the quality of ecological environment by making use of the long time series night light image data and Landsat image data from 1995 to 2020. And the variation characteristics of urbanization and ecological environment of urban agglomeration in the middle reaches of the Yangtze River are analyzed. By introducing the coupling and coordinated development model, the coupling coordination degree between urbanization and eco-environmental of urban agglomeration in the middle reaches of the Yangtze River is evaluated and its variation characteristics are analyzed. The research results show that: (1) The urbanization of the urban agglomeration in the middle reaches of the Yangtze River has experienced three stages: low level (1995-2005)-rapid development (2005-2015)-medium level (2020). It has gradually formed a trend of radiation around Wuhan, Changsha and Nanchang. However, there are still some imbalances in regional development. (2) The ecological environment has experienced three stages of stabilization-decline-recovery, but the overall quality is comparatively good and the change stage is basically consistent with urbanization. (3) The urbanization and ecological environment of Wuhan, Changsha and Nanchang have rapidly entered into the state of coordination, reached the medium and high degree of coordination. The surrounding cities which are closely connected with the central city also gradually transition from maladjusted state to moderate coordinated state. At the same time, more than half of the cities have been in the state of dissonance to varying degrees for a long time, but the overall trend is changing towards coordination. By 2020, only a few of these cities are still in the state of mild dissonance, and the rest have reached a state of basic coordination.