The transmission efficiency of the wireless power transfer system is affected by many factors， including the quality factor of the receiver. This research proposes a control model for determining and maintaining optimal values of the receiver’s quality factors to maintain maximum efficiency. Based on the LCC?S topology, the research first drew the relationship between the transmission efficiency and the quality factor of the receiver, and this paper presents an effective method to determine the optimal quality factor Q of the receiving coil. Then, a control strategy of the buck circuit is proposed to ensure that the system always runs at the maximum efficiency point. This strategy adopted phase shift regulation to adjust the phase angle of the voltage at the receiving end to ensure that the system always runs at the maximum efficiency point. Finally, the feasibility of the proposed method to determine the optimal value of quality factor Q at the receiving end is verified through simulation and a wireless charging experimental platform.