Abstract: Objective To study whether exposing to Microcystin(MC)was harmful to liver function.Methods Across section study was carried on in a small town near Tai-lake.The MC was detected in different sources of drinking water,using high sensitive ELISA.The liver functions(GPT,AKP,γ-GT)of different exposure groups were compared.Results There were significant differences in GPT and γ-GT among three exposure groups,especially in males other than HBV infection and swimming effect.Conclusion Exposing to MC affected the activity of SGPT and γ-GT.