Abstract: This article refers to the security of high-voltage filter inductor and the distributed capacitance of the transformer's secondary winding and introduces a phase shifted controlled full-bridge boost topology, which is applicable for high-voltage power supplies. The soft switch process of boost mode is analyzed by time subsection, the theoretically analyzed result is validated with Pspice simulation, then the boost circuit and buck mode are compared with resistant voltage trait of output filter inductor, cross regulation capability of multi-route output and transformer's magnetic unbalanced issue. The research indicates that the boost mode phase shifted controlled full-bridge converter performs better in cross regulation capability and the self-control of transformer's magnetic unbalanced issue, which is suitable for high-voltage applications.