Abstract: In base of the data of marine environmental quality of shellfish culture in Liusha Bay from May 2008 to February 2009, we comprehensively assessed the organic pollution and eutrophication of seawater, as well as the geo-accumulation and potential ecological risks of the sediments. Results show that the seasonal variation of salt and dissolved inorganic nitrogen in seawater are related with seasonal rainfall, while the dissolved oxygen, chemical oxygen demand and phosphate are related with phytoplankton bloom and shellfish culture. The assessment indicates that the seawater in Liusha Bay is clean with high nitrogen nutrients and low phosphate nutrients. The sediments have not been polluted by arsenic and lead, but slightly polluted by mercury and cadmium, and some moderately polluted by copper. The potential ecological risks of copper, lead, arsenic, zinc and chromium are slight, while those of mercury and cadmium are of medium degree.