The present invention discloses a plug-in box backboard PCB installation structure. The structure comprises cross beams applied and fixed with a backboard PCB, there are a plurality of cross beams, the length of each cross beam is larger than the width of the backboard PCB so that the cross beams can completely hold the backboard PCB, the two ends of the cross beams arranged in parallel are respectively fixedly connected with fastening rods, the cross beams are arranged in a horizontal direction, the fastening rods are arranged in a vertical direction, the fastening rods located at two sides are configured to fix the cross beams into one body, one sides, applied to the plug-in box, of the fastening rods and the cross beams are arranged in a coplanar mode to ensure that the cross beams andthe fastening rods can be applied to the plug-in box, allow the support effect at each position of the backboard PCB to be uniform and ensure the structure strength of the backboard PCB; and the two fastening rods are configured to fixedly connect with the plug-in box. The cross beams are fixedly connected into one body through the two fastening rods, the rods connected with the plug-in box are reduced to two rods, the fastening rods are not directly connected with the backboard PCB so that a larger connection piece can be employed, the operation in the dismounting and mounting process is lessand the dismounting and mounting efficiency is improved.