Abstract: To evaluate the genotoxicity of bifenthrin,the present study investigated the damage effects of different concentrations of bifenthrin on the DNA of hepatopancreas cells in Ruditapes philippinarum.After exposure to 0.05,0.10,0.15,0.20 mg/L bifenthrin for 25 days,hepatopancreas cells of Ruditapes philippinarum were extracted and assayed by using the single cell gel-electrophoresis(SCGE).The percentage of comet tail DNA(TDNA%),comet tail length(TL),olive tail moment(OTM) and Tail rate(TR) were used as the indicators of DNA damage.The results showed that,all indicators in all treatment groups increased significantly compared with those in the control group(P < 0.05).All indicators increased gradually according to the increased concentrations of bifenthrin.The correlation coefficient of r was greater than 0.99,which indicated that the concentration-effect relationship was observed in the experimental concentration range.TDNA% and OTM were the better experimental indices in the assessment of comet assay.The multiple-dimensional regression equation had significant statistic meaning(P < 0.01),which might be an effective way to estimate the exposure concentration of bifenthrin.