As an electric vehicle charging facility, the energy efficiency of DC chargers has been paid more and more attention. At present, the research on the energy efficiency of DC chargers mainly focuses on improving the energy efficiency measurement accuracy and energy efficiency measurement methods, and lack of research on the improvement of energy efficiency of DC charger. In view of this, this paper mainly studies the improvement of energy efficiency of DC charger, analyzes the power consumption composition distribution of main functional units, and focuses on the power conversion module The controller, LCD screen, auxiliary power supply and other components are optimized, the corresponding energy-saving and loss reduction schemes are proposed, and the targeted optimization solutions for each part are proposed to reduce the energy loss generated by each functional unit in the actual operation. The DC charger is improved according to the optimization scheme, and the effectiveness of the proposed energy-saving and loss reduction measures is verified by experiments. The research results of this paper are of great significance for the charging pile to improve the charging service level and energy efficiency, which is conducive to the rapid development of the field of electric vehicles and accelerate the implementation of energy conservation and emission reduction policies.