A hierarchical CuO nano-structure is prepared by directly growing CuO nanoflowers on carbon fiber fabric (CuO/CFF) via a hydrothermal method. The CuO/CFF is used as the electrode material of a supercapacitor for electrochemical energy storage. The supercapacitor displays superior electrochemical performance in aqueous electrolyte with the specific capacitance of 839.9F/g at the scan rate of 1mV/s, energy density of 10.05 Wh/kg and power density of 1798.5W/kg, which are the highest values for the CuO/CFF electrodes. Moreover, a flexible symmetric solid-state symmetric supercapacitor is also fabricated by using the CuO/CFF as electrodes. The solid-state supercapacitor exhibits a specific capacitance of 131.34F/g at the scan rate of 1mV/s with a power density of 145.12W/kg, and 95.8% capacitance retention after 2000 charge-discharge cycles.