Abstract: 【Objective】The pathogen causing Procypris merus disease and death was identified，and its virulence genes were analyzed to provide theoretical basis for disease diagnosis and effective prevention in future P. merus culture. 【Method】Pathogenic bacteria were isolated from the liver and kidney of diseased P. merus，and the isolated strains were identified by morphological observation，physiological and biochemical characteristics identification and 16S rDNA sequence analysis. The pathogenicity of the isolated strain was determined by artificial regression infection test，and the drug sensitivity test was carried out by disk diffusion method，and 18 virulence genes were detected by PCR.【Result】A Gram negative short bacillus（named 19042401）was isolated and purified from the liver and kidney of diseased P. merus. After morphological observation，physiological and biochemical identification and 16S rDNA sequence analysis，it was identified as Aeromonas veronii. The results of artificial regression infection showed that the strain had strong pathogenicity，with a lethal dose（LD₅₀）of 5.75×10⁷ CFU/kg. The results of drug sensitivity test showed that among 19 kinds of common antibiotics，strain 19042401 was sensitive to 6 drugs such as kanamycin，azithromycin and doxycycline，moderately sensitive to 7 drugs such as streptomycin，roxithromycin and gentamicin，and resistant to 6 drugs such as penicillin，enrofloxacin and amoxicillin.The results of the virulence gene PCR indicated that strain 19042401 carried 10 virulence genes，including Act，Aer，GcaT，Acg，OmpAI，Alt，Fla，Exu，Ser and AhyB.【Conclusion】A. veronii was the pathogenic bacterium causing the disease of P. merus，which has strong pathogenicity and carries 10 virulence genes. It is only sensitive to a few drugs and has different degrees of resistance to many commonly used antibiotics. Doxycycline can be used for treatment in aquaculture production.