A systematic study was conducted to identify and isolate a serologically pertinent antigen with high specific activity and low cross reactivity from Cysticercus parenchymal antigen. Differential centrifugation of the homogenate yield three particulate and one soluble fractions ; the $480{ imes}G$ pellets($CyL_2$), the $7650{ imes}G$ pellet($CyL_3$), the $100000{ imes}G$ pellet($CyL_4$), and $100000{ imes}G$ supernatant($CyL_6$). We compared antigenicity of these antigens to that or cystic fluid antigens($CyF_1$), saline extract of cystic wall($CyL_1$), and n-butanol treated $GyL_4$ antigen ($CyL_6$) based on SDS-PAGE and immunoblot techniques. The data obtained were as follows : 1) The ratio of O.D. value of ELISA against cysticercosis positive pool sera to that of negative pool sera was highest when using $CyF_1$ as antigen. However the ratio was relatively low in case of $CyL_{3.4}$ and $CyL_5$. 2) We have noted in previous paper that most strong antigenic activities are present in 63Kd band with low cross reactivities. An effective serologic reagent must contain components that are recognized by most infected sera. 63Kd band met this criteria and could be considered as a reliable band for the diagnosis of cysticercosis. As far as 63Kd band concern, $CyL_5$ showed most strong activities without disturbance of cross reaction by EITB in spite of low applicability to microplate ELISA. 3) $CyL_5$ could detect the serum antibody of cysticercosis even in very low titers, around cut-off values of microplate ELISA, by immunoblot. It also could detect the cross reactivities of Echinococcus species, which showed high absorbance value in micro plate ELISA and some sparganosis cases. Further purification of this antigen will be able to represents a antigen that can be used in the diagnosis of cysticercosis.