Three strains of pathogenic bacteria, DFL11-01, DFL11-02 and DFL11-03 were isolated from the diseased Babylonia areolata cultured in Hainan Province, and identified as Vibrio harveyi by regular physiological and 16S rRNA gene sequence phylogenetic analysis methods. The DFL11-01 was identified as causative agents via artificial infection test and the LD50 value was 2.6×10⁶ cfu/g. Drug sensitivity tests showed that the strain DFL11-01 was highly sensitivity to Ampicillin, Ceftriaxone, Piperacillin, Enrofloxacin, Lebofloxacin; medium sensitive to neomycin, tetracycline, ceftazidime, but resistant to azlocillin, rifampir, cefaclor and some other 12 kinds of antibiotics.