Commercial carbon fiber (T300) cloth as the original material is surface-treated by a two-step approach, lastly becoming a high-performance electrode. This kind of electrode has a high specific capacitance (42.2 F g −1 ), which is nearly a hundred times that of the original carbon cloth. After fabricating these electrodes into a symmetric supercapacitor device, it provides a high specific energy of 4.64 W h kg −1 at a specific power of 10 W kg −1 . Furthermore, the device showed long cycling stability (it keeps 92% capacitance retention after 1000 cycles), good rate capability, and low internal resistance. This work is expected to provide guidance for the research of structural supercapacitors based on commercial carbon cloth.