Abstract: Based on the data of the trawl fishing survey from Dongshan Bay in April (spring) and October(autumn) 2016,the characteristics of community structure and biomass distribution of fishery resources in Dongshan Bay were analyzed.A total of 128 species were collected,including 88 species of fishes,9 species of shrimps,19 species of crabs,4 species of cephalopods and 8 species of stomatopods,mainly dominated by warm water species.Clupanodon Punctatus,Thrissa vitirostris and Leiognathus brevirostris were the dominant species in spring,Charybdis japonica,Sardinella zunasi,Pisodonophis cancrivorus,Portunus hastatoides,Thryssa vitrirostris and Thrissa kammalensis were the dominant species in autumn,and the result showed that dominant species changed evidently during two seasons.Besides,the catch density indices of weight in spring and autumn were estimated to be 214.91 kg·km^-2 and 265.19 kg·km^-2 respectively,and the catch density indices of number in two seasons were estimated to be 12.51×10³ ind·km^-2 and 12.02×10³ ind·km^-2 respectively,and the result indicated that fishery resources displayed a decreasing tendency.Furthermore,the Margalef richness index,Shannon-weaner diversity index,and Pielou evenness index were respectively 5.112,2.179 and 0.635,the values in spring were significantly lower than those in autumn,and the biological diversity was at a lower level.