Abstract: Due to the large number of passive components, the traditional double switch forward soft switching converter has the disadvantages of larger prototype size and higher magnetic component loss. In order to solve this problem, firstly, the flexible multi-layer foil (FMLF) integration technology is used to realize the electromagnetic integration of large capacitors and magnetic components in circuits. Compared with the traditional magnetic integration technology, the volume of passive components can be further reduced and the utilization ratio of magnetic cores can be improved. Secondly, the use of permalloy strips section fill in column of air gap, it divided into multiple isometric stingy gap, both limits the magnetic leakage of the middle column winding, and narrowed the air-gap diffusion flux, effectively reduce the eddy current loss and winding losses caused by diffused flux, so as to effectively improve the power density of power supply and meet the demand of lightweight, miniaturization and high efficiency of new energy development. Finally, a 60 W prototype is built to verify the rationality of the application of the magnetic component.