As the performance requirements of MC-WPT systems increase, the temperature of the coupling mechanism or the power conversion circuit of a high-power power transmission MC-WPT system can change or even damage the system if the temperature is too high. The control of the temperature has become the key to the long-term stability of high-power MC-WPT systems. Therefore, this paper proposes a loss optimization structure for the coupling mechanism with layer gaps. Firstly, we take the power transmission performance as the entry point to design a coupling mechanism that can transmit high output power under the size limitation of the coupling mechanism; secondly, we analyze the mechanism and optimization method of heat generation due to losses in the coupling mechanism; finally, we optimize the thermal performance of the coupling mechanism in terms of improving the heat dissipation structure and reducing the heat generation due to losses.