Abstract: Based on the data from the macmobenthos surveys in Zhelin Bay and adjacent waters in Feb.,May.,Aug.,and Dec.,2013,the speciescomposition and seasonal variation of macrobenthos were studied.Krelatedsamples of nomparametrie tests were used to distinguish quarterly differences of species number for macrobenthos.The species replacement and migration were used to analysis quarterly variation of macrobenthos.The standand forthe dominant macrobenthos was IRI≥100.Results showed as follows:(1)The number of species was 88 in 2013,which belonged to 8 phylum.Thetop 4 phylum was Mollusca,Annelida,Arthmopoda,Echinodermata,and thenumber ofspecies was 41,26,7 and 7,respectively.(2)The species numberof Phylum did not existing signifi-cant difference seasonally.(3)The seasonal specieschangewas evident.The change of species was obvious withunstable communiies when the environment unfavored of macrobenthic survival was found from summer to winter.In contrast,the change of species was relatively insignificant with stable communities when the environment favoredthe survival ofmacrobenthoswasfound from winter to summer the next year.(4)Dominant species composition isrelatively stable.There were 9 species of domimant species by the surveysand they were Paphia undulate,Turritel-la bacillum,Rudiapes philjpinarum,Notomastus latericeus,Aglaophamus sinersis,Terebellides stroemii,Scolelepissquamata,Pseudopolydora hempi and Listriolobus bretirostris.Six dominant species appeared fortimes of more than2 seasons,accounting for 66.67%of total dominant species.The first dominant species in spring,autumn andwinter was Paphia undulata.The influence of aquiculture to dominant species of macrobenthoswas obvious in Zhe-lin Bay and adjacent waters.