We conducted a field survey on bird community structure in Dec. 2009 (flood period) and May 2010 (lower water period) by using transect method and simultaneous survey methods in Duchang Migratory Birds Nature Reserve of Poyang Lake, Jiangxi Province. We totally recorded 169 bird species belonging to 43 families of 14 orders, 17 species of them listed as national protected species. In addition 4 species, Siberian Crane (Grus leucogeranus), Common Crane (G.grus), Hooded Crane (G.monacha) and White-naped Crane (G.vipio) was recorded by the nature reserve administration during routine monitoring.The dominant birds recorded in the lower water period were species belonging to Passeriformes (47.4%), Charadriiformes (13.3%), and Anseriforms (9.6%). While in the flood period, birds species in Passeriformes, Charadriiformes, and Anseriforms were dominant ones and took 58.3%, 8.3% and 10.4% of the recorded species, respectively. The bird community structure changed obviously between the two periods. The highest bird diversity was recorded in crop land in the lower water period. While in flood period, the bird diversity index in crop land was as same as that in the open water. The dominant birds in the lower water period were Acridotheres cristatellus, Pycnonotus sinensis, Sturnus cineraceus, Passer montanus, and Streptopelia orientalis. Egretta garzetta and Acridotheres cristatellus were dominance in the flood period.