Objective: To investigate the infection of the first leptospirosis patient in Zhoushan in the past 40 years, and to evaluate the potential risks of host animal and local resident infection. Methods: RT-qPCR was used to detect leptospiral nucleic acid in a suspected case, local residents, and host animals (small mammals and pigs) in 2022. The 23S rRNA target gene was amplified by RT-PCR and sequenced to detect the infected genospecies. ELISA was used to detect leptospiral antibodies in the sera of suspected case and residents. Results: Leptospiral nucleic acid was tested positive in the acute phase of the suspected patient, but turned negative in the recovery phase. In contrast, IgM and IgG were negative in acute phase but positive in recovery phase. Leptospiral nucleic acid was tested negative in the sera of 69 residents, but was positive in the urine of 3 residents with positive IgM. The positive rate of IgM in sera of residents was 4.35% (3/69) and the positive rate of IgG was 8.70% (6/69). The positive rate of leptospiral nucleic acid in small mammal kidney was 30.00% (15/50), and the three pig urine were positive for leptospiral nucleic acid. The species in the sera of the suspected case in acute phase, 4 rat kidney specimens, and 2 pig urine specimens were identified as Leptospira borgpetersenii. The species in 3 urine specimens from local residents, 5 rat kidney specimens, and 1 pig urine specimen were identified as L. interrogans. Conclusions: The patient was confirmed with leptospirosis. The infection rates of Leptospira in host animals and residents were both high in the patient's place of residence.