The invention relates to an overhead line concrete pole number plate mounting method and a special mounting machine and belongs to the technical field of power supply maintenance and construction. The technical scheme includes that the special mounting machine comprises a substrate (1), an upper mounting plate (2), a lower mounting plate (3), a connector (4) and a mounting rod (5), the upper mounting plate is arranged on the upper portion of the front of the substrate, two end portions of the upper mounting plate are bent inwards to be perpendicular to the substrate, a downward V-shaped upper clamping support (6) is arranged at each of the two ends, perpendicular to the substrate, of the upper mounting plate, the lower mounting plate is mounted on the lower portion of the front of the substrate, two end portions of the lower mounting plate are bent inwards to be perpendicular to the substrate, and an upward V-shaped lower clamping support (7) is arranged at each of the two ends, perpendicular to the substrate, of the lower mounting plate. The overhead line concrete pole number plate mounting method and the special mounting machine have the advantages that the special mounting machine is simple in structure and flexible to use, pole number plates can be mounted quite conveniently, and the pole number plates can also be demounted, so that the problem of ascending a height of working personnel is solved, labor intensity is lowered, insulating effect is realized, and safety is guaranteed.