In the experiment, enterobacterial repetitive intergenic consensus (ERIC-PCR) was used to analyze the typing of the 105 strains of Aeromonas hydrophila collected from freshwater aquaculture area in Jiangsu, Henan, and Fujian. The genotyping technique was used to apply in the epidemiological investigation of the strains and evaluate the relationship of the genotype, regional distribution and the ecological niches. Electrophoresis prints was analysed by using Quantity one 4.6 and used UPGMA to make a tree plot to analyse hereditary character. 28 special genotypes were identified from the 105 isolates. Genotype ⅩⅤ was the dominant genotype, consisting of 20 strains, whereas genotypes Ⅳ, Ⅺ, ⅩⅪ, ⅩⅩⅤ, ⅩⅩⅥ, ⅩⅩⅦ and ⅩⅩⅧ contained only one strain. There is a tendency that the strains from the same geographic area or ecological niches could be clustered into one group. In addition, A. hydrophila from different regions and ecological niches might get together for the same genotype. The results suggest that there is likely some relevance between the genotype and ecological niche among A. hydrophila strains.