Trailer through beam

The utility model provides a trailer through beam, which comprises a through beam body. Longitudinal beams pass through the through beam body which is provided with a plurality of grooves along the direction of the trailer base plate. The upper parts of the longitudinal beams pass through the grooves. The upper end parts of the longitudinal beams are located inside the grooves. The upper top surfaces of the longitudinal beams and the upper top surface of the through beam body are then aligned and ensured to contact the trailer base plate simultaneously. The through beam body is thus made capable of supporting the trailer base plate together with the longitudinal beams simultaneously without additional cushion blocks. The cost is effectively reduced. Meanwhile, the trailer through beam is very convenient to use.