〔Abstract〕 Objective To study the role of presenilin in the reproductive development and oviposition ofSchistosoma japonicum(S.japonicum). Methods The 16, 18, 24 or 28 days post infection(dpi) worms were collected from the mice infected withS.japonicum, then the expression levels of presenilin in the 16, 18 or 24 dpiS.japonicumfemales were analyzed by real-time quantitative reverse transcription PCR(qRT-PCR); The ovaries were collected from 28 dpiS.japonicumfemales, then the expression levels of presenilin in ovary were analyzed by qRT-PCR. The paired schistosomes of 28 dpi were transfected with specific presenilin siRNA and culturedin vitrofor 10 days, then the morphological changes in reproductive organs, male-female pairing and egg production were observed after presenilin gene knockdown. Results The presenilin mRNA expression levels in females 24 dpi were markedly higher than those in females 18 dpi or 16 dpi, in both male and female parasites, higher amounts of the presenilin gene were expressed in ovary tissues. The RNAi of 28 days' pairing worms were treated with siRNA, after 10 days of culturein vitro, the results showed that compared with the control group and the Mock group, the male and female pairing rate of the experimental group decreased significantly; the results of confocal laser scanning microscope showed that in the interference group, the morphology of the reproductive system changed, the number of germ cells decreased and the morphology was abnormal. Conclusion Presenilin plays an important role in the reproductive development and oviposition ofS.japonicum.