Recently, there has been a lot of research in vanadium redox flow battery (VRFB) which is used as a large scale energy storage system and power supplier. Especially, graphite electrodes play an important role because they do directly act as electrochemical reaction in cell. In this study, commercial graphite felts were prepared by heat treatment in the range of 400 to 600 °C, controlling the condition of heat treatment such as air purity, heating processing time. As a result, the surface morphology and oxide of electrode were observed by SEM and XPS. Moreover, electrochemical evaluations such as CV (Cyclic Voltammetry) and impedance were performed in three electrode cell at room temperature, in which the kinetic properties of electrode were different with the condition of surface modification. Furthermore, small VRFB full cells constructed with the graphite felt showed the properties of charge and discharge profile corresponding to the above analysis and electrochemical test. Therefore, we will introduce the effect of heat treatment on the graphite felt electrode and its correlation in electrochemical reaction in more detail.