In this paper, the fundamental analysis and time domain analysis of CLLLC resonant circuits are described respectively, and a time domain model is established. For the output capacitor voltage, the forward Euler method is used to discretize the discrete capacitor voltage state model. By using the model predictive control method, the output voltage of the converter at the next moment is controlled, so as to achieve the effect of early control. Matlab/Simulink tools are used to simulate and verify the entire control circuit, and the verification results show that the model predictive control algorithm designed in this paper has good effects in voltage stability and responsiveness.