Abstract: The invention discloses a numerical simulation method for the overflowing of river channel structures based on finite volume method. The method firstly acquires plane geometric data, river section data and structure geometric sizes of the river channel. The river channel is discretized by using the one-dimensional finite volume element, and the primitive variable values are stored in the center of the element, wherein the position of the river channel structures is taken as the element special interface. The amount of water passing through the structure interface in each time step is calculated according to the structure overflowing formula. This amount of water is respectively deducted from and increased to the upstream element and the downstream element adjacent to the interface by applying the source item method. The primitive variable values at the special interface are reconstructed by adopting the non-reflection boundary conditions in order to ensure the continuity of calculation.