Aiming at the stability of bus voltage in island DC microgrids, a voltage optimization control strategy based on multi-step model prediction method is proposed in this paper. The predictive current controller is used to replace the traditional PI current controller, which effectively overcomes the shortcomings of the traditional lag control and improves the dynamic performance of the system. At the same time, the multi-step model predictive control method solves the shortcoming that the single-step model predictive control method can only ensure that the selected switch function combination is optimal in a control cycle. The simulation results show that the voltage optimization control strategy based on multi-step model prediction method can suppress the bus voltage fluctuation effectively, improve the dynamic and static performance and enhance the anti-interference ability of the system.