Abstract: The growth and stability of coastal wetland system depends on two processes of material balance. On one hand,the deposition of sediment from rivers makes saltmarshes and wetland prograding upward and seaward; On the other hand,sea-level rise,sediment compaction,subsidence of marsh and erosion by tidal channel system create accommodate space. The interaction of the two factors determines the complex evolutionary history of a coastal wetland. This paper discusses the sediment transport of the delta river,flooding,tide,and tidal channels system and its influence on the wetland.