In situ growth of Cu₂₊₁O (Cu₂O with metal excess defects) was achieved through a facile hydrothermal process by employing porous Cu foam (CF) as substrate and the precursor, meanwhile, graphene nanosheets (GN) were deposited onto the Cu₂₊₁O/Cu foam substrate. The GN/Cu₂₊₁O/CF hybrid electrode provides a large accessible surface area, and contact between GN/Cu₂₊₁O and current collector (Cu foam) with good conductivity facilitated electron/ion transport. When being used as a potential biosensor for nonenzyme glucose detection, cyclic voltammetry (CV) and amperometric electrochemical method to evaluate the electrocatalytic performance of GN/Cu₂₊₁O/CF, and the GN/Cu₂₊₁O/CF hybrid electrode exhibits multistage linear detection ranges with high sensitivity (3.076 mA mM⁻¹ cm⁻²) and the detection limit is 5 μM. Furthermore, the GN/Cu₂₊₁O/CF electrode also presented excellent repeatability, stability and reproducibility and selectivity. The design of GN/Cu₂₊₁O/CF hybrid electrode provided a useful strategy for design electrochemistry non-enzymatic biosensors.