The invention discloses a water-land coupling and distributing traffic system construction method taking a navigation cascade hub as a core. The method is realized by the following specific steps of: S1, extracting a logistics network graph from an current traffic base map so as to obtain navigation cascade nodes and a town node; S2, establishing connection between the navigation cascade nodes and the town node, wherein the town node is directly communicated with the navigation hub node; S3, computing a diffusion coverage area of goods and materials, according to a diffusion model for goods and materials, at each navigation hub node; and S4, matching freight transport output capacity of a target navigation channel with output needs of a cargo transportation output area, and updating a cargo transportation diffusion coverage area. According to the water-land coupling and distributing traffic system construction method, navigation and land transportation are integrated under a comprehensive scheduling background, current traffic resources are transferred more sufficiently, and a cascade traffic transportation value is brought into play; and matching between the cargo transportation capacity and regional consumption capacity is taken into a full consideration, so that the transportation capacity is saved.