An infectious disease outbreak in Penaeus vannamei Boone(Litopenaeus vannamei) occurred in Guangdong Province in 2012. For the diagnosis, and effective prevention and control of this disease, the pathogen was isolated and characterized via molecular biology. One isolate of Aeromonas caviae (ZHBX12016) was isolated. This strain could induce symptoms of natural disease in Penaeus vannamei and resulted in 95% mortality in 5 days by immersion infection, and with LD₅₀ of 6.43×103 cfu/mL via muscle injection. The isolate was Gram-nagative straight rod. Biochemical characterization of Galactose, Sucrose, Mannitol, Glucose, Arginine dihydrolase, Lysine decarboxylase and gluconate showed that the isolate was similar to Aeromonas caviae isolated from other aquatic animals. The 16S rDNA gene was amplified by polymerase chain reaction (PCR) and sequencing. Analysis of 16S rRNA gene showed that the isolate shared 97.7%-100% identity with A. caviae. The phylogenitic tree derived from 16S rDNA gene of Aeromonas showed that the isolate and A. caviae clustered into the same branch. Based on morphological, biochemical and physiological responses, pathogenicity and 16S rRNA gene analysis, the isolate was identified as A. caviae. The antibiotic sensitivity test showed that the strain ZHBX12016 was hypersensitive to chloramphenicol, terramycin, amikacin and furazolidone.