The invention discloses a river network modeling method which is used for analyzing and researching the river network by means of the complex network theory, and belongs to the technical field of hydrology. The modeling method abstracts the object river network into a directed network model and includes steps of defining evident changes of hydraulic characteristics of rivers in the object river network as nodes of the directed network model; defining riverways where river water flows through among the nodes as edges of the directed network model and defining flow direction of the river water as directions of the edges. The river network modeling method further quantitatively analyzes importance of the nodes and the edges in the river network according to the hydraulic characteristics such as the length of the riverways and runoff volume. Compared with existing normal hydrological models, the river network modeling method can well reflect real topological property of the river network and integrally analyzes and researches the real river network, importance of the nodes and the edges in the river network can be analyzed, and great significance in flood fighting, disaster relief, water resource protection and hydrological analysis and research and the like is achieved.