Sending and receiving resonator is a key part in wireless power transfer system, its performance directly determines the size of the transmission efficiency of the whole system. In this paper, the plane spiral coil is chosen as the sending and receiving resonator. The influence of coil properties (number of turns, substrate material, number of layers, etc.) on the coil parameters is analyzed by finite element simulation software HFSS, and the energy transfer characteristics between the resonators is analyzed. The simulation results show that the coupling factor between the coils has a greater effect on the transmission efficiency than the coil Q value. Finally, considering the coil performance and production costs, choose the best coil to make inkind and build a wireless power transmission device. The entire device is capable of lighting a 15 W LED bulb within 450 mm of the coil diameter of 2.5 times, and the transmission efficiency is more than 60%.