With the increasing demand for ocean resource development，unmanned underwater vehicles face problems such as heavy batteries and inconvenient charging during long-term operations，which limit their endurance. Underwater wireless power transfer technology provides a new solution for traditional wet plug charging methods. More importantly，its safety and convenience enable unmanned underwater vehicles to quickly replenish energy during mission execution，solving the bottleneck of endurance. In order to better understand the research trends of the related technology，the relevant research progress on efficiency optimization of underwater wireless power transfer technology is reviewed in this article. Firstly，the basic working principle of underwater wireless power transfer system is briefly introduced，and the impact of seawater environment on system performance is analyzed. Secondly， the research progress at home and abroad is summarized focusing on system modeling and system efficiency optimization. Finally，the development trend of underwater wireless power transfer technology is discussed.
