Abstract: ObjectiveTo investigate the current status of leptospirosis epidemic and the immunity level of health population in Sanmen, and get the information for the control and prevention of leptospirosis. MethodsThe antibody to leptospirosis was detected for clinically confirmed patients and health people by micro-agglutination test (MAT); Rats, frogs and the samples of midstream urine of cattle were taken to isolate the pathogen. ResultsA total of 587 serum samples from health people were detected, and 60 were positive (10.22%). The positive rate in the rats was 0.07%(icterohemorrhagic form). The result of the detection for the frogs (1400) and the samples of cattle midstream urine (140) were negative. ConclusionThe incidence of leptospirosis is high in summer and autumn, and young/middle-aged farmers are affected mostly. The serum antibody positive rate of health population is inconsistent with that of animal host. The surveillance in population and animal host should be strengthened.