The Cu_xO micro/nanomaterials with various novel morphologies have been synthesized on the surface of copper foil by a simple electrochemical method. The morphology of the Cu_xO crystal could be controlled by adjusting the electrolyte solution. The structure and morphology of as-prepared Cu_xO micro/nanomaterials were determined by scanning electron microscopy, elemental analysis, X-ray photoelectron spectroscopy and X-ray powder diffraction. The formation mechanism of these Cu_xO micro/nanomaterials was discussed. The Cu_xO micro/nanomaterial electrodes showed good electrocatalytic activity toward glucose oxidation and the performance of nonenzymatic glucose sensors based on these Cu_xO micro/nanomaterials was investigated in detail. As a typical representative, the nonenzymatic glucose sensor based on the Cu_xO_{NaClO4+CoCl2+SDS} micro/nanomaterials showed a wide linear range of 0.025–9.05 mM and a low detection limit of 14.3 ± 0.6 μM. The green synthetic method of simply adjusting the electrolyte is not only suitable for synthesis of Cu_xO with various morphologies, but also provides an easy way to prepare other metal oxide with different morphologies for constructing nonenzymatic glucose sensors.