Tetraclita japonica is a good bio-monitor for the marine heavy metal pollution. Tetraclita japonica is a fouling organism and commonly distributes in the rocky intertidal zone of Zhoushan Islands, which has high accumulation abilities of heavy metal. In order to investigate heavy metal pollution in Zhoushan sea area and its enrichment regularity in marine organisms, the accumulation abilities of Cu, Pb, Cd, Cr, As, and Hg in Tetraclita japonica are analyzed. The results show that content of Cu are much higher than that of Pb, Cd, Cr, As, and Hg in Tetraclita japonica, and there is also a significantly positive correlation between Pb and Hg content. According to its total quantity of accumulated metals, it could be seen that Tetraclita japonica from Daishan and Xiaoyang Islands are most severely polluted by heavy metal among the seven sampling sites studied. In comparison with the biological quality criteria for marine bivalves, metal contents in Tetraclita japonica are almost below the second standard value except contents of Pb and Hg. By contrast to the heavy metals of Cu, Cr, Cd, and As, Tetraclita japonica in Zhoushan Islands is contaminated by Pb and Hg quite seriously.