Graphite paper (GP) is one of the most common current collectors due to its high conductivity and low price. Therefore, it is very attractive to obtain high performance supercapacitor electrodes by improving the supercapacitive properties of GP. Here a simple electrochemical method is proposed to treat GP. The obtained electrochemically treated GP (ETGP) electrode shows significantly enhanced supercapacitive performances, which can be attributed to the increased electroactive surface area and introduced oxygen-containing functional groups. The specific capacitance of GP electrode is increased by as high as 25 times via this treatment. The resulting electrochemically treated GP electrode yields the specific capacitance of 64.9 mF cm(-2), which is even larger than those of recently reported pseudocapacitive electrodes. This work provides a simple method to fabricate high performance supercapacitor electrode.