Abstract: Aiming at the problems of poor dynamic performance of four-switch Buck-Boost converter due to the influence of voltage gain blind zone during operation mode switching, a three-mode control strategy based on deadbeat current predictive control is proposed. Firstly, the trajectory of duty cycle change in the middle mode of the four-switch Buck-Boost converter and the corresponding state space average model of the three operating modes are analyzed by graphical method, and the mode switching is realized smoothly. Secondly, the traditional current loop control is changed into deadbeat current predictive control, and the two-step method is used to compensate the control delay, so as to realize the predictive control of each mode and improve the dynamic response speed. The simulation results show that compared with the traditional control method, the improved three-mode control strategy proposed can reduce the output voltage fluctuation by 42.9% and 50%, and the recovery time by 50% and 48.5%, respectively. When the load surges to 100%, the output voltage fluctuation value is reduced by 40%, 37.5% and 35.7%, respectively, and the recovery time is reduced by 49.2%, 44.3% and 44.3%, respectively. Finally, a small power prototype is built to verify the superiority of the proposed control method.