Abstract: Using enzyme-linked immunoblot technique (ELIB). the antigenic protein components of water-soluble and urea-scluble antigens of Schistosoma japonicum eggs (JSEA, JEA-U) aad Paragonimus westermani adult worms (PAA, PAA-U) were analysed. The results showed that in both JSEA and JEA-U, 8 and 3 bands of polypeptides could be recogni-zed by sera from patients with schistosomiasis japonica (Sj). In both PAA and PAA-U, there were 9 and 2 bands of polypeptides respectively, which could be recognized by sera from patients with pagumogonimiasis skrjabini (Ps). The components of 36/37kDa in PAA and 20/21 kDa in JSEA were identified to be shared antigenic fractions existing between the two species of trematodes, which gave positive reaction against patient's sera from both S.j. and P.s., while PAA-U caused the reaction only with sera from patients with acute schistosomiasis. PAA-U might be useful to avoid cross reaction in the majority of schistosomiasis patients in the fields.