Abstract: Objective To evaluate the immunoprotective effect of schistosoma japonicum recombinant 31/32kDa protein (rSj31/32).Methods S.japonicum adult worm cDNA expression library was screened with Sj31/32 McAb as a catching antibody probe.The positive clone 312 was introduced as lysogens into E.coli Y1089 and induced by IPTG.Mice were vaccinated with rSj31/32 at weeks 0,2,4 and challenged with 40±2 S.japonicum cercariae at weeks 5.Results The rSj31/32 could induce 30.1% worm reduction rate and 63.2% egg reduction rate(P<0.01).It could reduce the mean areas and perimeter of egg granuloma.Conclusion The results indicated that rSj31/32 could result in protection against a subsequent challenge of S.japonicum in mice.It might be used as a promising vaccine candidate of S.japo nicunm.