Abstract: According to the characteristics of flow and sediment transports in the tidal river networks, the paper establishes a one-dimensional unsteady flow model for simulating tidal current sediment and bed scoursilting processes.Some relevant problems including moving-land-boundary, sediment-carrying capacity formula selection, sediment concentration at inner boundary cross-sections and their solving algorithms are discussed.Based on the hydrologic and topographic data of Dongjiang lower networks, the model verification shows good results for the flow transport characteristics and the river bed variation patterns for the tidal river networks.