Abstract: In the report, the effects of different concentrations of Cr⁶⁺ on the ingestion rate and the activities of two antioxidants（SOD and CAT） in the gill of Polymesoda erosa were analyzed, and the toxicity test was used to determine the changes of ingestion rate and two enzymes activities in gill tissue under different concentration gradients Cr⁶⁺ stress. The results showed that the effects of different concentrations of Cr⁶⁺ on the ingestion rate of P.erosa were significantly different, however, the general trend was same. With the increase of experimental time, the ingestion rate of P.erosa decreased, and the higher the concentration of Cr⁶⁺ was, the lower the ingestion rates of P.erosa was. The changes of SOD and CAT activities in the gill tissues of P.erosa were similar. With the experiment proceeding, both SOD and CAT activities increased firstly, and then, decreased. The higher the Cr⁶⁺ concentration was, the more obvious the decrease of SOD and CAT activities was, and the response speed of SOD to heavy metals was faster than that of CAT. Our findings can provide theoretical basis for the ecological risk assessment of chromium pollution, and also provide basic data for the prevention of shellfish chromium poisoning and the establishment of related molecular toxicology indicators.