Over the past half-century, with a dramatic increase of global population and rapid urbanization, the structure and function of global ecosystems have been strongly disturbed by human activities and have undergone unprecedented changes. More and more ecological and environmental problems, such as soil erosion, biodiversity loss, water pollution, etc., are a serious threat to national and regional ecological security. As one of the most dynamic regions of economic development in China, the Yangtze River Delta is confronted with ecosystem function deterioration and environmental degradation while the economy is growing rapidly. It is urgent to construct regional ecological security pattern to ensure sustainable development of the land space. Most previous studies on ecological security pattern mainly focused on biodiversity protection, ecosystem service maintenance, and landscape integrity. However, the relationship between ecological space and ecosystem service demand space is less considered, and so does the coupling of human socio-economic system and natural ecosystem. The research methods focused more on the exploration of source identification and resistance surface construction, and less on the construction of ecological corridor. Therefore, this study aims to scientifically link the ecological sources and urban demand space on the basis of identifying the regional ecological sources and high ecological demand areas through the analysis of regional ecological supply and demand, so as to expand the service scope and function of ecological space. In this study, ecological sources are identified from three aspects:habitat quality, importance of ecosystem services, and landscape connectivity. In terms of landscape connectivity, the method combining morphological spatial pattern analysis (MSPA) with possible connectivity (PC) index is used to identify areas with high connectivity at pixel scale. Thereafter, based on the spatial grid data of population and GDP, we identified the spatial pattern of regional ecological demand on a micro scale by using the ecosystem service value assessment method. Finally, based on the minimum cumulative resistance (MCR) model, we extracted ecological corridors among ecological sources and between sources and regions with high ecological demand, so as to construct and optimize the regional ecological security pattern. The results show:(1) the total ecological source area of the Yangtze River Delta region is 64911km², accounting for 32.51% of the total area, mainly distributed in southern Anhui Province and central Zhejiang Province; (2) the total area of high ecological demand patches in the region is 93038km², accounting for 46.60% of the total area, mainly located in Shanghai and Jiangsu Provinces; (3) the total length of regional ecological corridor is 11188.85km². The corridors among sources are mainly distributed along the Yangtze River and in the south of the region, and the demand corridors are mainly located in the east, middle and north of the region. To conclude, we incorporate ecological demand assessment into the framework of ecological corridor construction, providing a new idea for the construction of ecological security pattern. The results can provide decision-making reference for the ecological spatial protection planning and the optimization of land space development pattern in the Yangtze River Delta under the premise of jointly maintaining ecological security.