The use of Mya arenaria as a new sensitive biomonitor of butyltins pollution in the oceanic system was investigated. Field survey indicated that much higher levels of butyltin compounds were found in M. arenaria compared with the other species investigated. Using Mytilus edulis as a control organism, a 28 days exposure of tributyltin chloride (TBT) to M. arenaria for accumulation and subsequent 28 days breeding in clean seawater for elimination were conducted under laboratory conditions in order to confirm its high accumulation ability and characterize its kinetic behavior to TBT. Bioconcentration factor (BCF) of M. arenaria ranged from 15,538 to 91,800 after 28 days exposure. The rapid uptake and low rate to eliminate TBT of M. arenaria displayed first-order kinetics. M. arenaria shows potential as a new bioindicator to monitor TBT pollution in marine environment.