Abstract: The heat treatment of iron tetraphenylporphyrin chemically modified glassy carbon electrode has been described. The modified electrode by heat treatment shows good catalytic activity and stability for dioxygen reduction. Its catalytic activity is still maintained through 1000 cireles of cyclic voltametrie scans (100 V s~(-1)) in air saturated 0.05 mol L~(-1) H_2SO_4 solution. The effects of heat treatment temperature from 300 to 800 ℃ on the praparation and catalytic activity of the modified electrode have been studied. Using X.P.S, UV-VIS spectroscopy and Mass-spectroscopy the possible microstructure on electrode surface has been analyzed. The electrocatalytic and dynamic behaviors for dioxygen reduction at the electrode have been studied by cyclic voltametry and rotating disk electrode respectively. The rate constants of dioxygen reduction at the electrode in a variety of pH solutions have been measured. The catalytic reduction of dioxygen at this modified electrode belongs to irreversible processes including 2-electron to H_2O_2 and 4-electron to water.