Failure problem of the equalizing electrode O-ring of DC transmission converter valve was taken as the research object, the failure mode of the O-ring and the deposited chemical substances were analyzed. It was preliminarily determined that the failure of the O-ring might be caused by vibration and wear of the product; the working conditions of the equalizing electrode and the O-ring were analyzed; the running state of electrode in waterway was simulated by using simulation software; an equivalent vibration test system for equalizing electrode and O-ring was designed.The test results show that the vibration of the equalizing electrode needle can cause the electrode seal to wear and precipitate black powdery substance, and the failure of the equalizing electrode is directly related to the vibration operating environment of the equalizing electrode.The results of simulation analysis and equivalent test provide a reference for the study of the improvement scheme of the equalizing electrode O-ring.