When the dual-active-bridge DC-DC converter works in the boost and buck state, under the traditional single-phase shift control, the voltage mismatch will affect the power distribution of the converter’s leading bridge, lagging bridge and inductor, which in turn increases the on state loss of the converter. The dual-phase shift control with internal phase shift angle can change the voltage waveforms on the input and output sides, thereby optimizing the reactive power flowing through the leading and lagging bridges, increasing the degree of freedom and flexibility of control, and changing the power characteristics of the converter. On this basis, a dual-phase shift control strategy is proposed that the converter works in the boost and buck state, and the reactive power on the inductor is the optimization goal, which is set to reducing the overall reactive power and on state loss of the converter, thereby improving the efficiency of the converter. Finally, the effectiveness and superiority of the dual-phase shift control method are verified through experiments.