In recent years, the lightweight and miniaturization of on-board electrical equipment in electrified railways has become a research hotspot, which is the development direction of on-board electrical equipment. However, reducing the volume of electrical equipment will lead to the enhancement of electromagnetic interference between components, which will affect the normal operation of equipment. This paper will propose a solution to the problems of high coupling, excessive mutual inductance and serious electromagnetic interference between the coils of a miniaturized six-channel reactor, and design a new six-channel reactor structure with the combination of segmented core and electromagnetic shielding. This new structure has a significant inhibitory effect on the mutual inductance between the coils, weakens the coupling degree between the coils, reduces the mutual inductance value of the coils to 2%-20% of the original mutual inductance value, and ensures that the self-inductance of each coil remains unchanged, effectively eliminating the electromagnetic interference between the coils.