This paper presents a novel bidirectional DC-DC converter with high step-up/down voltage gain by using the coupled-inductor technique. The high step-up voltage gain is achieved when the energy is transferred from the battery to DC-bus, and the high step-down voltage gain is achieved from DC-bus to the battery. High efficiency is obtained since the energy stored in leakage-inductor is recycled. Also, the operating principles and voltage gain of the proposed converter are discussed in detailed. Finally, a laboratory prototype with battery voltage 24 V, DC-bus voltage 200 V and output power 200 W is implemented to validate theoretical analysis.