One of the most important reasons for the abnormal mortality of the cultured bivalve is the environmental contaminants, which induce suppression for the immune system of the bivalve. In this research, the immunotoxicity of marine pollutants on the clam Ruditapes philippinarum collected from the coast around Dalian was explored. The results indicated that types and concentrations of contaminants had important influence on the immunity and physiological indexes. In Pikou Sea area, owing to the lower content of heavy metal and oils, total haemocyte counts (THC), leucine aminopeptidase (LAP) activity and lysozyme (LYZ) activity of clams were significantly higher than the other three sea areas (P<0.05), and a lower haemolymph lipid peroxidation (MDA) level was also found. In Heishijiao area with higher content heavy metals and oils, the glutathione (GSH + GSSG) content of haemolymph in clams was significantly higher than the other three sea areas (P<0.05). And the superoxide dismutase (SOD) levels of haemolymph were higher (P<0.05) in clams collected from Zhuanghe Sea area, where a higher concentration of heavy metal was detected.