In recent years cultured sea scallop (Patinopecten yessoensis) dead on a large-scale in seas near Changhai County, Dalian, China, in summer. The main symptom is the abscess on adductor muscle. The transmission experience was improved to indicate that a bacterium isolated from natural infected focus, named XJ02 displayed intense pathological activity to scallops, and the symptom is the same to natural intention. The bacterium XJ02 identification test through morphological specificity, physical and chemical properties and 16S rRNA gene sequence analysis showed the bacterium is Vibrio chagasii. There has been no any research on the pathogenicity of V. chagasii. This article for the first time to find a more comprehensive's vibrio physicochemical properties of research. The dose-and temperature-dependent test indicated that the bacterium had the most pathogenicity at 19 ℃ while the concentration was 1.09×105 CFU/mL. The medicine sensitivity analysis that￠s to check Ampicillin, Benzylpenicillin, Ciproflxacin etc is sensitive during 20 drugs sensitive test, to Tetracycline, Doxycycline is not sensitive element.