Abstract: For a spacecraft installed with high sensitivity equipment, the accidental radiation of the equipment inside the cabin, coupled with that outside the spacecraft cabin through the cable and through the hole, can be received by the high sensitive equipment antenna outside the spacecraft cabin. The reception of the normal signal by the high sensitive device is disturbed in this case. In view of this situation, a new method of cable coating and hole plugging is presented to reduce the influence of electromagnetic radiation leakage on the receiving system. It is shown that the method improves the EMC of the satellite.