Abstract: Heavy metals have long been recognized as one of the most important problems in aquaculture and aquatic products safety area,with deleterious effects on aquatic benthic filter feeders.The research aimed to study the acute toxicity of zinc (Zn2+),cadmium (Cd2+),copper (Cu2+),chromium(Cr6+),selenium (Se4+) to Crassostrea plicatul.Using semi-static test method,the median lethal concentrations (LC50) were measured of five heavy metals Zn2+,Cd2+,Cu2+,Cr6+,Se4+ in Crassostrea plicatul.The results showed that the median lethal concentrations of Zn2+,Cd2+,Cu2+,Cr6+,Se4+ for 48 h to Crassostrea plicatul were 1447.00,28.16,12.25,1098.00,22.89 mg/L respectively; for 72 h were 231.62、12.24、4.23、539.02、9.12 mg/L; whereas for 96 h were 81.84、8.83、2.59、378.06、4.10 mg/L,respectively.Safety concentrations (SC) were 0.81,0.08,0.03,37.80,0.04 mg/L respectively.The order of the toxicity of these heavy metals was Cu2+ Se4+ Cd2+ Zn2+ Cr6+ in turn.The tolerance of Crassostrea plicatul to Cd2+,Zn2+and Cr6+ were relatively strong which were 17.60 times and 37.81 times, 8.18 times higher than the fishery water quality standards (GB11607-89),respectively.