Based on triangular grids, the planar 2-D flow and sediment mathematical model in natural branching river has been established by using the finite element method. Since the mass concentration and pre-estimated and verified iteration are used to solve the equations, the question of memory units and calculation velocity are settled quite well. Simulation calculation carried out on Tianxingzhou reach of the Yangtze River shows the result is closely fitted with the field data, which showes that the model is creditable, it can provide the technical support for research on the natural branching river regulation.
