Novel rose rock-shaped cuprous oxide anchored graphene nanocomposite (Cu2O-GN) is successfully synthesized by a simple and efficient one-step solvothermal method. Notably, the reduction of graphene oxide (GO) and deposition of nano-Cu2O on GN occur simultaneously during the polyol reaction process. The nanocomposite is systematically characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). We also explore the formation mechanism of Cu2O-GN including the concentration effect of the precursor, precipitation agent, GO, and heating rate on the morphology of the resulting nanocomposite. It is noteworthy that Cu2O is gradually decorated on the large sheets of GN to form ordered three-dimensional nanostructure with the optimized concentration of GO, which is crucial to the growth of the final nanoarchitectures. In addition, the electrochemical properties of the Cu2O-GN nanocomposite are investigated by cyclic voltammetry and galvanostatic charge-discharge measurements. The composite shows a favorable electrochemical capacitance (416 F g−1 at 1 A g−1), rate performance and cycling stability. Also, a high specific capacitance and good retention point to its promising applications as electrode materials in supercapacitors.