Abstract: Anqing beach wetland is a typical wetland along the lower and middle reaches of Yangtze River. The wetland is very important in maintaining the stability and the biodiversity riches of the ecosystems in the region. Biodiversity is an important function of wetland ecosystem. The plantation of wetland in Anqing varies greatly with reeds, Arundo donax, Salix matsudana, Populus deltoids. The paper mainly studied the functions of the three kinds of wetland: Salix matsudana wetland, Arundo donax wetland, and Populus deltoids wetland,compared the differences of plant biodiversity among the three kinds of wetlands. It is showed that the indexes of diversity and species richness were the highest in Populus deltoids wetland, and the lowest in Arundo donax wetland. The Simpson index was the biggest in Salix matsudana wetland, and smallest in Arundo donax wetland which indicated that the species dominance focused on a few plant species, but it is not so definite in the Arundo donax wetland. In the beach wetland of the middle and lower reaches of Yangtze River the herbs species were more concentrated. The index of eneness was the highest in planted Populus deltoids wetland, and lowest in Salix matsudana wetland. The biodiversity also varied according to the difference of altitude of wetlands. The law is that with the growth of altitude, the biodiversity will decrease. In Populus deltoids forest,the difference of forest age did nothing to the biodiversity and to the richness of plant species.