Abstract: In the context of rapid urbanization, the imbalance between supply and demand of ecosystem services in the water network area of southern Jiangsu is becoming increasingly serious. Building a security pattern from the perspective of supply and demand is an effective way to ensure the healthy development of the region. In this study, the Chenghu area with typical water network characteristics was taken as the object, and the ecological security pattern was constructed based on the evaluation of ecosystem supply and demand. The results showed that: 1) The spatial distribution of the ratio of ecosystem service supply and demand in Chenghu area showed significant spatial differentiation characteristics. 2) Based on the relationship between supply and demand, 36 ecological sources, which were high-value areas for ecosystem service supply, were identified, and 22 demand sources were mainly distributed in urban built-up areas. 80 ecological corridors, distributed in a network pattern, were extracted, and 21 supply and demand corridors effectively connected ecological sources and demand sources. The study identified 21 ecological nodes and 32 supply and demand nodes. 3) An ecological security pattern of 'three zones, seven belts and two groups' was constructed. The three zones are the supply core areas delineated based on the distribution of ecological sources. The seven zones are the supply protection zones and supply-and-demand adjustment zones determined according to the corridors. The two groups are the high-demand groups delineated with reference to the demand sources. This study provides a reference for strengthening the protection of ecological security in waternetwork areas and promoting the balance between supply and demand of ecosystem services.