Abstract:With global climate change and continuous urbanization exacerbating flood disasters, urban flood resilience and ecosystem services have become the focus of research. Clarifying the coupling coordination relationship between urban flood resilience and ecosystem services can provide significant decision-making reference for urban flood control, disaster reduction, and ecological civilization construction. Based on the comprehensive application of projection pursuit based on sparrow algorithm model, InVEST model and coupling coordination degree model, this study analyzes the spatiotemporal patterns of urban flood resilience and ecosystem services (water conservation, water purification, soil conservation, and climate regulation) in the Yangtze River Delta urban agglomerations from 2000 to 2020, and attempts to explore the spatiotemporal evolution characteristics of the coupling coordination degree between them. The results show that: (1) The level of urban flood resilience in the Yangtze River Delta urban agglomeration presents a N-shaped trend, with a spatial pattern of Shanghai > Jiangsu > Zhejiang > Anhui, indicating that cities with higher economic levels exhibit stronger urban flood resilience. The impact of economic resilience, social resilience and infrastructure resilience is much greater than that of natural resilience. Economy is the main factor affecting fluctuation in urban flood resilience, and natural resilience is a key weakness in improving urban flood resilience. (2) There is significantly spatial heterogeneity in the ecosystem services, but their spatial distribution is stable from perspective of time dimension. The southern regions with high vegetation cover provide higher ecosystem services. Water conservation and water purification services demonstrate a good trend in general, soil conservation service presents an inverted N-shaped increase, and climate regulation service displays a weak downward trend. (3) The coupling coordination degree between urban flood resilience and ecosystem services is relatively stable during the research period, and tends to be consistent with the spatiotemporal changes of ecosystem services. Among them, the coupling coordination degree between urban flood resilience and water conservation service shows a weak trend of first decreasing and then increasing, with a best overall performance, while the coupling coordination degree between water purification, soil conservation and climate regulation services has a weak decline. From perspective of space, the coupling coordination degree between urban flood resilience and ecosystem services shows a trend of high in the south and low in the north, gradually weakening from southwest to northeast. The cites with higher ecosystem services tend to have better the degree of coupling coordination, and improves with the increase of ecosystem services. Therefore, from perspective of improving ecosystem services, it is necessary for the Yangtze River Delta urban agglomeration to promote the coordinated development of urban flood resilience and ecosystem services according to local conditions and classification.