The invention relates to a processing method of a graphite felt electrode for an all-vanadium redox flow battery. The method comprises the step of processing and modifying the surface of a graphite felt by combining an oxidation method and an ammoniation method, concretely, firstly, performing oxidation processing on the graphite felt by using the oxidation method: washing the graphite felt, oven-drying, placing the dried graphite felt in a reaction tank, introducing oxygen, and heating to oxidize the graphite felt; secondly, performing ammoniation processing on the graphite felt: introducing ammonia water, and heating to ammoniate the graphite felt under high pressure to realize the modification; and thirdly, washing the modified graphite felt, and oven-drying to obtain the graphite felt electrode for the all-vanadium redox flow battery. The method provided by the invention is simple, the effect is obvious, the safety and the application are realized, and dangerous chemicals such as strong acids and strong bases can not be utilized. According to the method, the operation is convenient, the application cost is low, impurities such as amorphous carbon on the graphite felt surface can be removed without damaging the graphite felt surface, and the number of nitrogen-containing functional groups on the graphite felt surface can be remarkably increased, thereby enhancing the vanadium ion adsorption capacity, and improving the electrochemical property.