Lithium cobalt oxide (LiCoO₂) is one of the most widely used anode materials for energy storage of 3C digital products. The development of high-voltage LiCoO₂ cathode material will further increase its energy density and battery endurance. In a variety of material modification methods, bulk doping and surface modification are the both effective means to improve the performance of high-voltage LiCoO₂, and have extremely high academic and industrial application values. In this paper, we summarize the research progress of high-voltage LiCoO₂ by introducing common materials used for bulk doping and surface modification of LiCoO₂ cathode materials, and their surface modification, preparation methods, modification mechanisms, and synergistic effects. Moreover, existing problems and future development trends are also pointed out.