Abstract: The occurrence of disease is becoming more and more serious with the expansion of Haliotis discus nanri breeding scale, but so far no special reports focus on the research of these diseases.In order to provide some basic information for disease prevention and control of H. discus nanri, a dominant bacteria strain was isolated from the foot lesions and digestive gland of obviously dying individuals which were showing overt symptoms and proved to be the pathogen by recurrent infection experiment.The disease symptom of the pathogenic bacteria was observed carefully while biochemical characteristics and drug susceptibility test of the pathogenic bacteria were also detected separately.It turned out that the disease symptom was not significantly at the initial stage, and festering holes of different sizes could be just found on the foot of H. discus nanri after a period of time.The results of physiological and biochemical analyses showed the pathogen was Vibrio alginolyticus which was sensitive to 21 kinds of antibiotics such as flumequine and florfenicol and so on.It highly recommend that drug sensitive experiment should be necessary to carry out every time with the purpose of screening out the appropriate effective drugs to prevent and control the V. alginolyticus in H. discus nanri production process.