In this paper a ternary complex was reported. The chemical composition of the complex was [Fe(C7H5O3)(C9H6NO)]2, which was determined by elemental analysis, fluorescence spectroscopy, UV-visible spectra and IR spectra analysis. In this reaction salicylic acid coordinated with Fe(III) ion by carboxylic ion, and the phenol hydroxyl did not participate. The oxygen atom and heterocyclic nitrogen atom of 8-hydroxyquinoline were bidentate-coordinated with Fe(III) ion, forming a pentaheterocyclic. Extended the absorption of the compex into the whole visible-light region, the color of its powder and the concentrated solution showed black, the diluted solution was purple. When the excitation wavelength was 300 nm, the ternary compound emitted a strong fluorescence at 409 nm. The inhibitory effect of the ternary complex on the growth of E. Coli was studied by using spectrophotometry. The result showed that the growth of E. Coli was promoted when the concentration of the ternary complex was lower than 2 mmolL-1, however it was inhibited when the concentration beyond 2 mmolL-1. And the more higher the concentration was, the more stronger inhibition was. That was to say the complex had a bidirectional biological effect on the growth of E. Coli.