The invention discloses a high-voltage pulse liquid-phase discharge repair method for a lithium cobalt oxide material in a spent lithium battery. The method comprises the following steps: firstly, mechanically separating a spent lithium ion battery with a mechanical separation method in order to obtain lithium cobalt oxide waste; putting the lithium cobalt oxide waste into a lithium hydroxide solution; and implementing electrochemical performance repair of the lithium cobalt oxide material with a high-voltage pulse liquid-phase discharge method. The method has the advantages of simple technical process, low energy consumption and small environmental influence. The lithium cobalt oxide material being repaired by discharge treatment has high electrochemical performance, and can be recycled as a positive electrode active material of the lithium ion battery.