A novel high step-up DC-DC converter with ZVS turn-on switches and ZCS turn-off diodes based on several existed techniques such as coupled-inductor, active clamping, stacked capacitor and interleaved technique is designed and implemented in this paper. The main objective of proposed circuit is soft-switching operation. The leakage inductance of coupled inductors resonates with two secondary-side capacitors during steady-state operating modes. When the converter is operated at different resonant frequencies, ZVS turn-on and ZCS turn-off can be respectively accomplished by some power switches and rectifying diodes. Besides, by applying interleaved technology, the capacity of circuit can be increased. Operating principles, steady-state analysis, and component parameter designs are presented. Hardware prototype with 24V input voltage, 400V output voltage and 800W output power is implemented to prove the feasibility of proposed converter. The highest efficiency is around 95.6% when operating at 450W.