Abstract: The large capacity intelligent power distribution unit is a kind of core equipment on manned spacecrafts. Its complex working principle involves a conspicuous issue of electromagnetic compatibility. With regard to the three main functional blocks of such a unit, the method of absorbing, filtering, and reasonable choice of components, the PCB board design and the shielding design are used, to effectively inhibit the electromagnetic interference. Meanwhile, the problem of the interference superimposition generated when high-power DC/DC converters are working in parallel is solved. The modification is verified by experiments and it is shown that there are no overrun work points, which indicates that the EMC design of the large capacity intelligent power distribution unit meets the EMC requirements.