The invention discloses a treatment method of carbon felt for vanadium batteries, which comprises the following steps: oxidizing and activating carbon felt in 60-100 DEG C sulfuric acid for 0.5-4 hours or oxidizing and activating carbon felt in 20-30 DEG C sulfuric acid for 12-48 hours, and washing with water to obtain the activated carbon felt. Compared with other sulfuric acid or nitric acid oxidization methods, the invention firstly uses an alkaline solution to soak and wash the hydrophobic oil adhesive substances influencing the oxidizing process on the carbon felt surface, and then carries out the sulfuric acid oxidizing treatment, thereby increasing the oxo groups and other hydrophilic groups on the carbon felt molecules and enhancing the hydrophilicity and electrochemically active ion adsorption capacity of the carbon felt. The invention has the advantages of short treatment time and favorable carbon felt activation effect, and enhances the electrochemical activity of the carbon felt and the generation current value of the carbon felt as the vanadium battery electrode.