Abstract: The properties of water soluble complexes of Fe 2+ and TPPS 3 in the pH=5.2～5.9 HAc-NaAc buffer have been studies by the absorption spectroscopy and scanning porlarography.The results obtained shown that Fe 2+ and TPPS 3 would react completely in 15 min. at 90℃;H + partakes in the electrode reaction ;The composition ratio of the electrical activity complex is Fe: TPPS 3=1:1.The peak current of the electrical active complex reduced is proportional to the Fe 2+ comcentration .