Abstract: In order to make the photovoltaic system can output high DC voltage stably,a novel design of ultra-high Boost DC-DC converter is proposed. The converter adopts coupled circuit Boost structure and adds a new gain regulation unit. The new switching unit reduces the voltage stress and voltage spike of the switching device. The coupling inductor and switching capacitor can reduce the voltage and current peak of the device,and absorb the leakage energy of the coupling inductor. The output of the converter is stabilized by closed-loop control. The working mode of the circuit is analyzed,and the performance of the converter is compared with that of the typical high-Boost converter in recent years to test the anti-disturbance performance of the converter. According to simulation and experiment,the stability and robustness of the converter under closed-loop control are verified.