In the field of wireless power transfer (WPT), it is of significance to maintain the high transmission efficiency between the transmitting and receiving circuits. However, due to the temperature and other uncertain factors, the deviation of the receiver's intrinsic frequency will lead to the decrease of the transmission efficiency, which is an urgent problem to be resolved. In view of the detuning problem, a new method of tuning using the capacitor regulator is proposed. The structure of the capacitor regulator tuning circuit is introduced first in this paper. Then, combined with the two-coil model of WPT system, the maximum system transmission efficiency under the tuning effect of the capacitor regulator is analyzed and discussed. MATLAB is utilized to analyze the system transmission efficiency in different resonant states, while the magnetic simulation model is established by Maxwell. Furthermore, the experimental verification platform is designed simultaneously. The simulation and experimental results demonstrate that the design method can improve the coupling state between the resonant coils and improve the transmission efficiency from 54.3 to 73.4% in the detuned state. This method has an important reference and guidance significance for the future research of WPT system.