The invention provides a tool for assembling a display assembly. The tool comprises a slide rail and a pressure plate, wherein a step is arranged on the slide rail; the step is configured to support the display assembly; the display assembly can slide on the step in a length direction of the step; one end of the pressure plate is arranged on the slide rail; the other end of the pressure plate is suspended; and the pressure plate is configured to limit the display assembly in an up-down direction. According to the tool for assembling the display assembly, the pressure plate is fitted with the slide rail, so that the fixing and sliding functions of the display assembly are realized; and the tool is simple in structure, is convenient and reliable to operate, improves the production efficiency, reduces labor intensity of staff, and avoids and quality and safety hidden danger, so that the purposes of downsizing staffs and improving efficiency are achieved.