Chemical vapor deposition (CVD) and normal pulse voltage (NPV) are adopted to construct high-quality graphene-wrapped CuO nanoflowers grown in situ on copper foam (CuO NP@G/CF) as an efficient oxygen evolution reaction (OER) electrocatalyst. The CuO NF@G/CF electrode exhibits a small overpotential of 320 mV to drive a current density of 10 mA cm-2 with a low Tafel slope of 63.1 mV dec-1. This enhancement in OER performance stems from the synergistic effect between highly conductive graphene and hierarchically porous CuO nanoflowers with a number of high-density active sites and open spaces.