Abstract: As a potential indicator organism of freshwater pollution,the Mudsnail(Cipangopaludina cathayensis)was used to study the effects of Cd²⁺ on antioxidant enzymes and lipid peroxidation. The animals were exposed to a series of Cd²⁺ concentration(0,1.5,3.0,6.0 and 12.0 mg/L)for 96 h. Parameters including superoxide dismutase(SOD),glutathione peroxidase(GPx),catalase(CAT),glutathione S-transferase(GST),glutathione(GSH)and malondialdehyde(MDA)in the hepatopancreas tissues of Cipangopaludina cathayensis were determined at 24,48,72 and 96 h,respectively. The results showed that with the increasing of Cd²⁺ concentration,SOD,GPx,CAT,GST and GSH activities showed a trend of "rise and decline" at 24 h,while all decreased at 96 h. With the exposed time prolonging,SOD,GPx,CAT,GST and GSH also showed "rise and decline" at the same Cd²⁺ concentration. Meanwhile,the contents of MDA in hepatopancreas tissues of Cipangopaludina cathayensis increased with the time prolonging and Cd²⁺ concentrations increasing. These results suggested that the parameters of the hepatopancreas tissues of Cipangopaludina cathayensis were sensitive to Cd²⁺ toxicity,and could be used as biomarkers to evaluate Cd²⁺ pollution in water environment. Hepatopancreas could be used as a target organ to detect Cd²⁺ toxicity.