Abstract: In order to produce specific monoclonal antibodies for immunodiagnosis and immu noprophylaxis in hydatid disease, a monoclonal antibody cell line NIA2 secreting specific antibodies was established, through fusion of myeloma cells SP2/0 and spleen cells of BALB/c mice immunized with hydatid fluid from a local (Ningxia) patient and repeated screenings and clonings. The specificity was assayed via ELISA, immunoprecipitating and ultramicroscopy. Antibody titer of 1:2560 was obtamed in the supernatant of tne culture medium by ELISA and a high titcr of 3:163840 in seeded ascitic fluid of mice of the same isolate. Immunoglobulin subclass of the NIA2 secreting antibody was deter-mined to be IgG1 which showed no cross reaction to Cysticercus cellulosae. Cloned cell lines from the hybridomas were found consistent in secreting anti-Echinococcus gronulosus antibody through serial passage in tissue culture for ten months.