Abstract: The output ripple is large in the high-voltage switching power supply (HVSPS) due to the high-frequency switching tubes. To suppress the ripple, the DC high voltage converter part of HVSPS is improved, and a new structure based on multi-inductor coupled quadratic BOOST is adopted. Firstly, the main working principle of the DC high voltage converter is deduced, and the minimum ripple condition after the introduction of multi-inductance coupling is obtained. It is found that it greatly improves the voltage gain of the converter and reduces the voltage stress of the switch tube. At the same time, the magnetic integration technology is used for the key component of coupling inductance components (CIC), and an easy and reliable realization method of CIC is induced. Through theoretical analysis in-depth, modeling and simulating by SABER and ANSYS of the main circuit and CIC, the results show that under the condition of minimum ripple, not only can the coupled inductor magnetic components meet the magnetic flux requirements, but also the output voltage of the proposed HVSPS has the characteristics of high gain and micro ripple.