In the context of actively responding to the national "dual carbon" strategic goals, it is particularly important to explore the changes in carbon sinks in Blue-Green Spaces and the path to carbon sink enhancement. This article takes the Changsha Zhuzhou Xiangtan urban agglomeration as the research object, measures the Blue-Green spatial carbon sink based on land use data and carbon density coefficient from 2008 to 2022, and analyzes its spatiotemporal differentiation characteristics and influencing factors. Research has found that: (1) the overall carbon sink in the Changsha Zhuzhou Xiangtan region during the study period averaged 1.5156 million tons, showing a fluctuating trend overall; The average carbon sink in the blue space during the research period was 13400 tons, showing a continuous downward trend overall; The trend of green space as the main source of carbon sink is consistent with the overall carbon sink amount; (2) During the research period, the changes in carbon sinks in the Changsha Zhuzhou Xiangtan urban agglomeration maintained a certain degree of stability, and the spatial distribution center showed a "northeast southwest" spatial distribution pattern. The influence of the southwest region on the spatial pattern of carbon sinks gradually increased; (3) The degree of land use and population density respectively dominate the two paths of carbon sequestration in the Changsha Zhuzhou Xiangtan urban agglomeration, and their changes are influenced by multiple factors, especially the joint effect of urban land use degree and economic development, urban population density and economic development, which has the most significant impact on urban carbon sequestration.