Whereas it is well documented that Acinetobacter baumannii is associated with human clinical infections，there are few studies to date that reports it as a pathogen for aquatic animal.In the present study，one bacterial strain was isolated from diseased channel catfish (Ictalurus punctatus) from Qingjiang reservoir，Yichang，Hubei Province，China and named as CH016，which could be cultivated on freshwater agar and formed the round，white，smooth and margin-trim clone.Inoculating the strains to channel catfish for lethality indicated the germ had pathogenicity and the same bacterium could be isolated from these animals.The biochemical tests，the sequence analysis results of 16S rDNA sequence and phylogenetic analysis demonstrated that the microorganism isolated from channel catfish was A.baumannii.