Siderophore of Aeromonas hydrophila(Ah) J-1 was purified from culture supernatant by polyamide column chromatography, eluted by double-distilled water, ethyl acetate precipitated, lyophilized, then the white powder was collected, and demonstrated by CAS and Arnow assay. The siderophore was phenolate, composed of 2,3-dihydroxybenzoic acid (2,3-DHB), lysine, glycine and tryptophan by HPLC. Being cultured iniron-deficient medium, the purified siderophore could stimulated the growth of Ah N9a which siderophore production is poorly positive and reverse the inhibition growth of EDDA. It suggested that siderophore could promote growth of bacteria and might play an important role in bacteria infection.