The removable gooseneck trailer can use the lifting cylinder installed on the vehicle to support the front part of the semi trailer body on the ground. After the tractor is separated from the saddle of the semi trailer, the tractor is driven away from the semi trailer. When the tractor leaves, the front part of the semi trailer can be placed on the ground through the lifting cylinder, and the lifting cylinder can be continuously manipulated to convert the gooseneck platform into a semi trailer ladder, thereby solving the problem of the large rear part of the gooseneck lowbed trailer. Difficult loading and unloading of mechanical engineering machinery and mining machinery.