Abstract: Spherical mesoporous NiO powders were synthesized by a hydrothermal-thermal decomposition method, and their morphology and structure were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and N₂ adsorption/desorption analysis. The electrocatalytic performance of NiO powders were systematically studied by cyclic vohammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). It is found that the prepared mesoporous NiO powders are in spherical morphology with a specific surface area of 35 m²·g^-1 and an average pore size of 15.88 nm. They show good electrocatalytic activity for ethanol oxidation; the oxidation current increases with increasing ethanol concentration and scan rate. The current decay at 0.60 V for 1000 s is as low as 0.075%, indicating good stability. CV, CA and EIS measurements show that ethanol oxidation reaction on the spherical mesoporous NiO is a diffusion-controlled process.