Bi-directionally isolated DC-DC converter is widely used in electric vehicles powered by super capacitor energy storage. To realize zero voltage switching (ZVS) process of all switches in converter and improve efficiency of bi-directionally isolated DC-DC converter, a new control strategy of bi-directional active bridge converter is proposed. A parallel resonant inductor is added in the bridge converter. The drive signal is compensated by the method of duty cycle compensation. The current value of resonant cavity is solved. Appropriate resonant inductor value is selected to control the phase difference between primary side and secondary side voltage of the bridge structure during resonance process. The bi-directionally isolated converter is controlled by pulse width modulation(PWM) processor after comprehensive modulation. ZVS process of all switches in bi-directionally isolated DC-DC converter is realized. Experimental results show that the new control strategy can effectively improve efficiency of bi-directionally isolated DC-DC converter.