To improve the specific capacitance of graphene based supercapacitor, new ternary graphene/Mn3O4/Cu(OH)2 composite was synthesized by two-step method. First, graphene/Mn3O4 composites with different weight ratio (G : Mn = 1 : 1, G : Mn = 1 : 4, G : Mn = 1 : 7 and G : Mn = 1 : 10) were synthesized by mixing and annealing method. Second, Cu(OH)2 rods were deposited on Cu foil. Afterwards, graphene/Mn3O4 composite powders were deposited on Cu(OH)2/Cu copper current collector as working electrodes. The samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. The XRD analysis revealed the presence of graphene/Mn3O4. The presence of Mn3O4 was also confirmed by Fourier transform infrared spectroscopy and Raman spectroscopy. Graphene/Mn3O4/Cu(OH)2 composite electrode with the weight ratio of G : Mn = 1 : 7 showed the best electrochemical performance and exhibited the largest specific capacitance of approximately 266 F g2−1 at the scan rate of 10 mV/s in 6 M KOH electrolyte. In addition, other electrochemical measurements (charge-discharge and EIS) of the G/Cu(OH)2/Cu, and G/Mn3O4/Cu(OH)2/Cu electrodes suggested that the G/Mn3O4/Cu(OH)2/Cu electrode is promising materials for supercapacitor application.