In order to make the wireless power transfer system, the fabrication process of coils and the design of electric insulation and high thermal conductive materials are proposed by taking high current inductor system as an analogy. The fabrication process of the coil is developed for high current inductors. The copper plate is pressed and folded double at two fulcrum points to produce coils. The developed process restrains the cracks in the coil, compared with the conventional process involving the bend of rectangular wire in the lateral direction. The electric insulation coatings on the coil are developed. The electrical breakdown strength of the developed coatings is slightly higher than that containing polyamideimides. The developed material has a higher thermal conductivity of 0.83 W/m K. The high thermal conductive potting materials are developed to use between the coil unit and the aluminum case. The developed potting material has low viscosity (7.2 Pa s at 60°C), high thermal conductivity (6.2 W/m K), high glass-transition temperature, high thermal shock resistance and high volume resistivity compared to conventional one containing silicon rubber and Al₂O₃.