The paper proposes a method that add a variable capacitor bank to the LCC resonant converter for adjusting the resonant frequency and solving the problem of the system resonant frequency deviation during the reflected impedance of IPT system energy receiver of the electric vehicle is changed. The functional principle of the LCC resonant converter is analyzed, and the main parameters of the system are determined by the fundamental wave analysis method. The controlling algorithm by adjusting variable capacitor bank is designed to adaptively adjust the size of variable capacitor when the reflected impedance of energy receiver is changed, so that resonance frequency of the LCC resonant circuit is close to the driving frequency of the inverter circuit, and weak inductance is maintained. To achieve the ZVS function of the resonant converter switching tube within a wide range of load impedance changes, so switching losses and switching stress is reduced. The effectiveness of the method is verified by MATLAB/Simulink simulation experiments.