［Purposes］ At present, graphite felt electrodes are widely used in all-vanadium flow batteries due to their low cost and excellent catalytic performance, but poor hydrophilicity and low chemical stability limit their development. In order to improve the performance of graphite felt electrodes, the method of introducing catalysts was used to modify the graphite felt electrodes.［Methods］ Cr₃C₂ was used as the cathode catalyst for the VO²⁺/VO⁺₂ redox couple in the all-vanadium redox flow battery. Cr₃C₂ was characterized by X-ray diffractometer, scanning electron microscopy and X-ray energy dispersive spectrum. Electrochemical tests and charge-discharge tests were carried out on the modified electrodes.［Findings］ The morphology of Cr₃C₂ can effectively improve the electrochemical activity of the electrodes. In electrochemical tests, Cr₃C₂ exhibited good electrochemical activity and reversibility in the VO²⁺/VO⁺₂ redox process. In the charge-discharge test, the modified battery had a discharge capacity of 92.1 mA·h after 50 charge-discharge cycles, which was 17.1 mA·h higher than that of the blank battery. The voltage efficiency of the modified battery after cycling reached 86.14%, which was higher than that of the blank battery (80.84%).［Conclusions］ Cr₃C₂ is a promising cathode catalyst for improving the electrochemical performance of vanadium redox flow batteries.