Thirty five pathogenic bacteria verified by artificial infection from the livers of diseased eels were subjected to sequencing and phylogenetic analysis.DNA was extracted by CTAB method from each isolate,the 16S rRNA genes were amplified using universal bacterial primers,and then the 35 isolates were identified by restriction fragment length polymorphism (RFLP) analysis,sequences analysis and phylogenetic analysis of the 16S rRNA genes.The phylogenetic tree was constructed.The results indicated that these pathogenic bacteria belong to six genera and one family of two major groups (γ-Proteobacteria and Firmicutes).The Aeromonas genus is predominant (occupied 63%),including Aeromonas hydrophila,Aeromonas veronii,Aeromonas jandaei,and Aeromonas punctata.The Bacillus genus is second dominant.The rest are Yersinia ruckeri,Citrobacter freundii,and species of klebsiella geuns,Pseudoalteromonas genus and Enterobacteriaceae family.