Abstract: Objective The Three-North Plain is situated at the estuary of Hangzhou Bay, which represents one of the most active regions in China with regard to water conservancy construction in the southeast coastal region of China. During the traditional period, the construction of water conservancy projects represented by pond(beitang) and seawall(Haitang), spearheaded the advancement of the local economy, production, culture, forming a traditional human settlement system with indelible water conservancy imprints. In the context of new urbanization, it is of paramount importance to re-examine and comprehend this traditional water conservancy human settlement pattern, in which nature and humanity are harmoniously integrated, for the future of human settlement space planning. Methods This paper investigates the impact of pond and seawalls construction on the Three-North Plain habitat system by using historical literature research method and morphological graphical analysis method, and GIS as a technological support tool. Firstly, an analysis is conducted on the geographic environment of the construction of the pond and seawalls at the regional scale, followed by an examination of their subsequent impact on the local farmland pattern and land texture after their completion. Subsequently, from the settlement scale, the role played by water conservancy facilities in shaping the layout and morphology of the settlement is delved into. Finally, from the vantage point of social organization, with Shenshiqiao taken as a case in point, the local management organization and mode within the context of traditional water conservancy construction are analyzed in detail. Results The Three-North Plain"s distinctive geographic environment and climatic conditions have historically resulted in a range of challenges, including recurrent droughts and floods, tidal wave incursions, and soil salinization. Therefore, water conservancy construction in the Three-North Plain centers around two main aspects. Firstly, ponds are constructed at the foothills to store fresh water for irrigation purposes. Secondly, seawalls are erected in the coastal regions to safeguard against tidal waves and salinity intrusion. Collectively, these two components constitute a dual water conservancy system characterized by “internal storage and external obstruction,” which serves as a crucial factor in interconnecting and facilitating the development of other spatial elements within the local living environment. In terms of the pattern of farmland, the construction of the water conservancy systems of the pond and seawalls not only facilitated the formation of agriculture, but also prompted the people to implement production adaptations to further improve the water conservancy systems, resulting in different land textures: the Louzhao polder in the area of the pond, and the Zaogang Salt Pond, Jingbang Polder, and the Regular Polder in the area of the seawalls.With regard to the settlement system, the characteristics of the water conservancy facilities exert a profound influence on the settlement construction method: the pond convey irrigation water through a reticulated water network, and the settlements are laid out in a group-like layout at the nodes of the network; the seawalls are crossed by a line, so that the settlements are laid out in a linear layout with the seawalls as the reference (linear scattering, comb-toothed, herring-bone, and linear encircling). At the level of social organization, the construction of water conservancy projects and the maintenance of interests have led to the formation of local management organizations with the family as the core, and the establishment of robust water conservancy social relations. Conclusion This study focuses on the characteristics of the traditional habitat system in the Three-North Plain region in the context of water conservancy construction from three aspects: water conservancy-farmland pattern, settlement layout and social organization, and further provides reference for the construction of a contemporary habitat spatial system with local characteristics in the new period of urbanization.In light of its significance as a heritage site that encompasses both natural and cultural values, traditional water conservancy merits renewed examination and appreciation in the context of urbanization. Specifically, in addition to focusing on the entity of traditional water conservancy projects, attention should be paid to the spatial elements associated with them, such as agricultural landscapes and settlement systems. This is necessary in order to form a holistic protection and management mindset to give full play to the shaping of the spatial pattern of human settlements by water conservancy. Furthermore, it is essential to proactively incorporate traditional cultural elements associated with water conservancy, such as ritual practices and literary works, and facilitate the modernization of traditional water conservancy heritage value. Finally, in the context of rural revitalization, attention should be paid to reconstructing the relationship between people and traditional water conservancy, vigorously advocating community participation, enhancing the residents" sense of identification with traditional water conservancy, so as to build a contemporary living environment in line with the local characteristics of the Three-North Plain.