Abstract: To study the specificity and sensitivity and evaluation of therapy efficacy of the purified Schistosoma japonicum 31/32 kDa(Sj31/32)antigen in the diagnosis for the schistosomiasis japonicum,schistosomiasis sera were detected with purified Sj31/32 antigen and SEA by ELISA.The positive rate of anti Sj31/32 antibody in the acute and chronic schistosomiasis japonicum were 100% and 95%,while the positive rate of anti SEA antibody were 97.4% and 90%.No cross reaction was produced by Sj31/32 antigen,while some nonspecific reaction were emerged by SEA with normal human,patients with Paragonimiasis and Clonorchiasis.The negative conversion rate of anti Sj 31/32 antibody were 52.5%、72.5% and 82.5% respectivty at 3,6 and 12 months after chemotherapy while the negative conversion rate of anti SEA antibody were 15%、37.5% and 50%.The results indicated that Sj31/32 antigen might have higher sensitivity and specificity than SEA in the diagnosis of schistosomiasis japonicum and have the value of evaluation before and after chemotherapy.It might be used in the clinical diagnosis of schistosomiasis japonicum.