The nanoporous Co 3 O 4 thin films were prepared on indium tin oxide (ITO) glasses by an electrodeposition method. The surface morphology and composition of the nanoporous Co 3 O 4 films were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDS) and X-ray photoelectron spectroscopy (XPS). The results show that the as-deposited nanoporous Co 3 O 4 film is constructed by many interconnected nanoflakes with thickness of about 40 nm. The cyclic voltammetry (CV) measurement indicates that the nanoporous Co 3 O 4 films exhibit remarkable electrocatalytic activities for the hydrogen peroxide ( H 2 O 2) reduction which shows that it is a good candidate to be employed as electrode materials for electrochemical sensing of H 2 O 2. Further analysis indicated that the detection sensitivity of the sensor was 1.357 mA mM-1 cm-2 and the detection limit was estimated to be about 0.2 mM.