In order to improve the efficiency of the electric propulsion system, this paper considers the loss of the composite energy storage system, the fluctuation of lithium battery discharge power rate and the state of charge of the supercapacitor, and proposes the model predictive control strategy. Compared with the fuzzy logic control strategy, the current of the lithium battery under the model predictive control strategy is relatively smooth, the loss of the composite energy storage system is relatively reduced by 16.31%, and the efficiency is increased by 4.91%. Simulation results show that the proposed control strategy can effectively reduce the loss of composite energy storage system.