The utility model relates to a mounting tool for an interior decorative plate of a top cover, which is used for preventing the interior decorative plate of the top cover from being folded and polluted during the assembling process. The mounting tool comprises a frame and a support bracket, wherein the frame comprises upright columns and a bottom plate; the upright columns are fixedly connected with the bottom plate; a chute is formed on the bottom plate; the support bracket comprises a support column and a support plate; the support plate is fixedly connected to the upper end of the support column; the lower end of the support column is provided with a sliding block matched with the chute; the upright columns are arranged at two corners of the long side of the bottom plate; a positioning hook is arranged in the middle of the long side of the bottom plate; the upper surface of the bottom plate is provided with a plurality of storage boxes; and handles are arranged on two short sides of the bottom plate. The mounting tool can realize fast mounting of the interior decorative plate of the top cover and effectively prevent the interior decorative plate of the top cover from being folded and polluted during the assembling process; meanwhile, the assembling time of the interior decorative plate of the top cover is saved, and the feeling of fatigue of assembling personnel is reduced to a great extent.