Novel three-dimensional nitrogen-doped activated graphene-like nanosheets (3-D NAGNs) have been synthesized from inexpensive ion exchange resin, by using the an efficient activation-graphitization-doping synchronous strategy. The 3-D NAGNs sample has been systematically characterized by the X-ray diffraction, Scanning electron microscope, Transmission electron microscopy, X-ray photoelectron spectroscopy and Nitrogen adsorption-desorption techniques. The analysis results indicate that the 3-D NAGNs has a high specific surface area of 1815.6m2 g−1, a desirable crystalline structure and a satisfactory nitrogen content of 3.62% in atomic ratio. The as-prepared 3-D NAGNs electrode demonstrates excellent electrochemical performances for supercapacitors in 6M KOH aqueous solution electrolyte. A considerable specific capacitance of 383.2F/g is obtained for the 3-D NAGNs electrode via charge-discharge at a current density of 1.0A/g. It also displayed a very high cycle stability of 98%, compared with the initial capacitance, after 5000 cycles at a very high current density of 10A/g.