Abstract: The understanding of evolutional process in Meimaosha in the south passage of the Yangtze River Estuary may provide scientific base for the construction of reservoirs along the river. According to data of charts and insitu water and sediment change for about one hundred years, especially the recent field measures obtained in 2003 and 2004, the form history and evolutional process of the Meimaosha were discussed. The results showed that the formation and growth of Meimaosha had undergone three phases, i.e. the erosion of local beach, the growth of spitting and the formation of sand ridge. Meimaosha exhibited characters of tidal sand ridge as its middle axe had a good stability along the direction from northwest to southeast under the action of steady and driving flood and ebb tides in the passed half century. It is likely that the construction of the reservoir project will change the whole south passage to a new type watercourse suitable for water and sediment passing.

Key words: Yangtze River Estuary, Meimaosha, evolution of erosion and accumulation, reservoir project