Abstract: Exploring the law of interaction between urban construction and low-carbon economic development is of great significance to achieving high-quality sustainable development in the region. Based on this, this paper takes the Changsha-Zhuzhou-Xiangtan urban agglomeration as the research area, comprehensively use the decoupling development model and gray correlation method to analyze the interactive relationship and driving factors between urban compactness and carbon emission intensity. The results show that: (1) From 2005 to 2017, the coupling compactness of the average compactness and various types of functional compactness of the Changsha-Zhuzhou-Xiangtan showed an overall upward trend, but the coupling coordination degree of each urban area still has a large room for improvement. （2) During the study period, the carbon emission intensity of Changsha-Zhuzhou-Xiangtan showed a year-on-year downward trend. The rate of change of carbon emission intensity varies slightly among the urban areas. In general, it can be roughly divided into three types: high carbon emissions stage (2005-2007), continuous emission reduction stage (2008-2011) and low-carbon optimization stage (2011-2017). (3) The average compactness and carbon emission intensity of the Changsha-Zhuzhou-Xiangtan urban agglomeration are in a strong decoupling relationship in most years. A few years are characterized by recession decoupling and other conditions. The decoupling status and degree of each urban area vary slightly over the years. （4) The temporal and spatial correlation characteristics of the decoupling state of UC and CEI in Changsha-Zhuzhou-Xiangtan urban agglomerations and the value of each drivers are different. On the whole, the degree of influence from weak to strong is government participation, technological innovation, population quality, urbanization level and industrial structure. We should pay more attention to the coupling and coordination of all operating systems in the process of urban construction in the future. And we should combine the resource endowment of the city to innovate and create a low-carbon development model while attaching importance to high-quality urban development model.