Abstract: Four numerical simulation methods for tributary water exchange in plain rivers, which are the method of ratio between arterial and tributary, the method of storage of bottomland,the method of storage of cell and the method of reverse analysis are briefly introduced, and the four methods are used to calculate the water exchange between Shuzhou River and Huangpujiang River. Calculation results show that the method of storage of bottomland and the method of reverse analysis have high simulation accuracy.