A novel nonenzymatic glucose sensor was prepared based on a Cu coralloid granule/polyaniline (PANI)/reduced graphene oxide (rGO) nanocomposite modified glassy carbon electrode (GCE). The PANI nanowire array/rGO nanocomposite was synthesized by using an in situ chemical oxidative polymerization method, and then was cast onto a GCE surface. Cu coralloid granules were constructed on PANI/rGO/GCE by constant potential deposition. The Cu/PANI/rGO nanocomposite was characterized by scanning electron microscopy, X-ray energy dispersive spectroscopy, X-ray powder diffraction and Fourier transform infrared spectroscopy. The electrochemical and electrocatalytic behaviors of the Cu/PANI/rGO/GCE towards glucose oxidation were evaluated by cyclic voltammograms, electrochemical impedance spectroscopy, chronoamperometry and amperometric method. The amperometric response of Cu/PANI/rGO/GCE showed high catalytic activity towards the oxidation of glucose with a wide linear range of 0.01–9.66 mM, high sensitivity of 603.59 μA cm⁻² mM⁻¹ and low detection limit of 1.34 μM (S/N = 3).