A novel cobalt-tetraphenylporphyrin/reduced graphene oxide (CoTPP/RGO) nanocomposite was prepared by a ¦Ð-¦Ð stacking interaction and characterized by ultraviolet-visible absorption spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FTIR) and electrochemical impedance spectroscopy (EIS). The CoTPP/RGO nanocomposite exhibited high electrocatalytic activity both for oxidation and reduction of H2O2. The current response was linear to H2O2 concentration with the concentration range from 1.0 ¡Á 10?7 to 2.4 ¡Á 10?3 mol L?1 (R = 0.998) at the reductive potential of ?0.20 V and from 1.0 ¡Á 10?7 to 4.6 ¡Á 10?4 mol L?1 (R = 0.996) at the oxidative potential of +0.50 V. The H2O2 biosensor showed good anti-interfering ability towards oxidative interferences at the oxidative potential of +0.50 V and good anti-interfering ability towards reductive interferences at the reductive potential of ?0.20 V.