The pathogen of carp dropsy in Shandong Province was se par ated and confirmed to Aeromonas cav iae by methods of vir ology and art ificial infect ion .An inact ive vaccine with high immunogenici ty against car p dr opsy was made by a simple technological pr ocess .The safe ty , immunological protect ion and valence of this vaccine were studied , and an oral vaccinat ion was carried out in fishery .