this paper discusses the contactless power transmission system. The magnetic coupling model and structure required by contactless power transforming system with high efficiency are set up according to the analysis results. Then, advantages and disadvantages of various power converter models are investigated with circuits of compensation and efficiency promotion to design the best main circuit structure of converter. However, by simulation experimental results, the contactless transmission system is confirmed with high safety and efficiency. Finally, the eontaetless power transmission system with output voltage of 31V and output current of 11A is confirmed.