Mollusks living in seas can accumulate organochlorine pesticides (OCPs). The residue levels of selected OCPs: dichlorodiphenyltrichloroethane (p,p'-DDT, o,p'-DDT, p,p'-DDE, p,p'-DDD), hexachlorocyclohexanes (alpha-, beta-, gamma- and delta-HCH) in gastropod and bivalve species collected from ten coastal cites along the Chinese Bohai Sea were investigated from 2002 to 2004. The species included nine kinds of mollusks: Rapana venosa, Neverita didyma, Scapharca subcrenata, Mytilus edulis, Amusium, Crassostrea talienwhanensis, Meretix meretrix, Sinonovacula constricta, Ruditapes philippinarum, Mactra veneriformis. The results showed that OCPs widely existed in the mollusks organisms. p,p'-DDT, p,p'-DDE, beta-HCH were the major compounds. Statistical analysis (One-way ANOVA) showed that the contents of OCPs in these mollusks did not change obviously from 2002 to 2004. Principal component analysis (PCA) was also used for determining the polluting characters existing in this selected field.