The invention relates to a retarder mounting support, comprising an L-shaped plate arranged in a right-angle bending shape and sloping plates connected with two end parts of the L-shaped plate, wherein each sloping plate is provided with a kidney-shaped hole fixed with the rubber blanket of the retarder; two plate surface of the L-shaped plate are respectively provided with mounting holes matched with the kidney-shaped holes; at least two sets of mounting holes are provided, and each set includes two holes with the distance therebetween consistent with the hole distance of installing holes in a locating support. According to the technical scheme, when the position of the locating support fixed on an underframe varies, the three mounting holes in the L-shaped plate are all available to be mounted and fixed with the locating support; and therefore, the retarder mounting support can be applicable to the mounting of various kinds of retarders, and the weight of the mounting piece is reduced due to the mounting holes.