Marine bacteria from the samples of sea sediments and seawater were directly plated on isolation media and the biodiversity of isolates was examined with DNA fingerprinting.542 single colonies were obtained from the media.ARDRA with enzyme Hinf I revealed 16 operational taxonomic units(OTU) which were dominated by OTU5 group which accounts for 19 isolates,and OTU7 group which accounts for 11 isolates.The biodiversity of isolates from these two dominant OTU groups was further investigated by a genomic fingerprinting technique, ERIC-PCR.The results indicated that there were 12 different ERIC-PCR types present among the OTU5 group while only 4 among the OTU7.The data indicated rich diversity profiles of marine microorganisms were presented in the East China Sea.