Transition metal selenide has stimulated much research interest in energy storage and conversion, due to its excellent electrical conductivity. beta-Cu2Se with special crystal structure is considered as super-ionic conductor, of which the diffusion coefficient is as large as a liquid. The fast ions and electrons conductor beta-Cu2Se with uniformly dense nanowire crossing with each other directly on nickel foam is prepared via simple one-step solvothermal grow method for 4 h, avoiding conductive agent and binder. The feature much benefitting for electrons and ions transfer enable the beta-Cu2Se-4h electrode delivers specific capacity as high as 182.4 mA h g(-1) at current density of 2 mA cm(-2), which is still 105.6 mA h g(-1) even at high current density of 50 mA cm(-2), and excellent cycling stability of 85% after repetitively charge-discharge 10,000 times. The fabricated asymmetric supercapacitor (beta-Cu2Se-4h//AC) achieves maximum energy and power density is 48 Wh kg(-1) and 5500 W kg(-1).