Aiming at the problems such as low transmission efficiency and limited use of non - contact power supply system, this paper designs a new type of rotatable loosely coupled transformer by COMSOL simulation software, and builds an experimental platform as the core components.In order to improve the transmission efficiency of the system as the main purpose, the transmission performance of the system in static and rotational conditions is tested for different influencing factors, and the power factor fluctuation in the experiment is analyzed and solved. Finally, the transformer is optimized by comparing the simulation data with the experimental results.