Rainfall runoff simulation method based on sub-basin and one-dimensional finite volume element

The invention discloses a rainfall runoff simulation method based on sub-basins and a one-dimensional finite volume unit. The method comprises the following steps: firstly, dividing a drainage basin into natural sub-drainage basins, then discretizing a river reach corresponding to each sub-drainage basin by adopting a one-dimensional finite volume unit, and after the drainage basin discretization is completed, carrying out slope production and confluence process calculation on each sub-drainage basin by adopting a hydrological method; and then, according to the length weight of each finite volume unit of each river reach, distributing the confluence process of each sub-drainage basin into each finite volume unit, and after the water distribution is completed, carrying out one-dimensional hydrodynamic process simulation of the whole drainage basin water system. The method can give full play to respective advantages of a traditional hydrological model and a one-dimensional hydrodynamic model, not only gets rid