In recent years, substantial efforts have been devoted to investigating the electrocatalytic activity of transition metal oxide catalysts, especially delafossite oxides have been proved to exhibit remarkable activity toward the oxygen evolution reaction (OER). Herein, the electrocatalytic activity and stability of CuScO2 hexagonal plates (around 3-4 μm) for the OER in alkaline solution were investigated. The micron sized CuScO2 with well-defined hexagonal plate morphology was prepared through a facile hydrothermal method. Moreover, its crystal structure, morphology, surface chemical states, thermal stability, and electrocatalytic performance were studied. The CuScO2 powder exhibits efficient catalytic activity and good long-term stability towards the OER in 1.0 M KOH. An optimal electrode of Ni foam supported CuScO2 powders needs an overpotential of 490 mV to afford a benchmark current density of 10 mA cm-2 and is able to sustain galvanostatic OER electrolysis for 18 hours with little degradation of 33 mV.