The aim of this study was to isolate the pathogens of ulceration on the body surface in Plectropomus leopardus.Two strains were isolated from the skin,blood,kidney and spleen of mortal P.leopardus.One strain coded 1031 could cause the mortality of healthy P.leopardus independently in artificially infected experiment and were proved to be pathogen to ulceration of P.leopardus.Based on the results of morphological observation,physiological and biochemical characteristic analysis,strain 1031 was identified as Vibrio.16S rDNA gene sequence further proved that strain 1031 belonged to V.harveyi.Phylogenetic analysis based on 16S rDNA gene and hsp60 gene indicated that strain 1031 showed the highest level of similarity to V.harveyi with bootstraps of 97%.The expected 382 bp-nucleic acid fragment of V.harveyi toxR gene was amplified using stain 1031 as a template.These results indicated that the pathogen of ulceration on the body surface in P.leopardus was V.harveyi.The antibiotic sensitivity analysis showed that strain 1031 was susceptible to florfenicol,gentamicinum (120 μg) and rocephin,but high resistant to norfloxacin,enrofloxacin,azithromycin,doxycycline,etc.