The viral disease of penaeids is indistinct but highly dangerous because their symptoms are often masked by some secondary ones.In order to gain knowledge on how to prevent the occurrence and spread of this viral disease, diagnostic studies on the early phase of the hepatopancreatic parvo-like viral (HPV)disease of cultured Penaeus chinensis was conducted using immuno-serological techniques. The purification of HPV was successfully done by density gradient ultracentrifugation of cane sugar. The viral disease of penaeids is indistinct but highly dangerous because their symptoms are often masked by some secondary ones. In order to gain knowledge on how to prevent the occurrence and spread of this viral disease, diagnostic studies on the early phase of the hepatopancreatic parvo- like viral (HPV) disease of cultured Penaeus chinensis was conducted using immuno-serological techniques. The purification of HPV was successfully done by density gradient ultracentrifugation of cane sugar.