Abstract: he pathogens of Babylonia areolata "acute death syndrome" in Hainan were isolated and purified, artificially infected, 16S rDNA analized, and physiological and biochemical characteristics identificated. The results show that the pathogen is Vibrio harveyi. Drug sensitivity test results show that the pathogen is sensitive to the common antibiosis drugs such as enrofloxacin, sulfa, but resistant to penicillin. Pathological changes in the gill, hepatopancreas, gastropods, digestive tract and kidney are as follows: cell degeneration, necrosis, and blood cell infiltration.