Recently, the problem of heavy metal pollution has attracted many attentions in global scale. The problem of heavy metal contamination in fresh and processing shellfish products is urgently to be solved due to their strong ability of heavy metal enrichment. As the only existing natural alkaline polysaccharide, chitosan has strong ability of heavy metal chelating. In this paper, the molecular structure characteristics and adsorbent mechanism of chitosan in absorbing and removing heavy metals are analyzed. The importance of biological adsorbent on the removal of heavy metals was discussed in this paper. It was investigated of chitosan on heavy metals removal for economic shellfish products, such as oysters and scallop. Finally, considering the industry and cost requirements, suggestions for the future research on the topic of heavy metal removal from shellfish are proposed.