In this paper, zero voltage switching (ZVS) high step-up DC-DC converter with coupled-inductor is proposed. A coupled-inductor and two capacitors are used for raising the voltage gain. Two capacitors are charged by the coupled-inductor in parallel and discharge in series. Therefore, high step up voltage is built by these capacitors and the coupled-inductor. The energy of the leakage inductor is recycled by an active clamp circuit (including a switch and a capacitor). By simple control, both the main switch and the active clamp switch can achieve zero voltage switching. The operating principle and detailed analyses are discussed. Finally, a prototype circuit with 24-V input voltage, 400-V output voltage, and 200-W output power is implemented. Experiment results shows advantages of the proposed converter and the analysis results are correct.