Abstract: We analyzed the residues of polychlorinated biphenyls (PCBs) in the seawater, sediments and cultured shellfish of Dong-shan Bay by gas chromatography to evaluate the risks of the residues to human health and edible safety. The results show that the PCBs contents at the bottom were higher than those at the surface of seawater, and those in summer (August) were higher than those in spring (May). Overall, the PCBs contents declined from mid-bay to out-bay with highly significant correlation between suspended matter contents and PCBs contents at the bottom of seawater. Moreover, PCBs contents at the surface of sediments were high in near shore but low in mid-bay and out-bay with highly significant correlation between TOC contents and PCBs contents. The deleterious effects on biology from the residues of PCBs were not obvious. In addition, there were clear differences of PCBs residues among cultured shellfish species. As for the capacity of PCBs enrichment, Saccostrea cucullata, Sinonovacula constricta and Paphia undulate were the best, then were Tegillarca granosa and Chlamys nobilis, and then Ruditapes philippinarum and Haliotis diversicolor. In conclusion, the cancerogenic risk index of cultured shellfish is acceptable. The level of PCBs residues in cultured shellfish in Dongshan Bay is medium among cultured shellfish in coastal Fujian Province.