The invention provides a high-voltage wire length measuring bracket and relates to the technical field of overhead transmission line construction. The high-voltage wire length measuring bracket comprises a bracket body between a tensioner and a wire bracket; a guiding component arranged on the bracket body in the vertical direction; a mounting base in sliding connection to the guiding component in the vertical direction; a laser speed meter disposed on the mounting base; and at least two stopping wheels disposed on the side of the mounting base. The high-voltage wire length measuring bracket provided by the invention realizes the displacement of the mounting base in the vertical direction through the guiding component. The use of the mounting base enables the laser speed meter to synchronously move with the wire and avoids the resistance of the wire caused by excessive limitation of the wire so as to ensure the normal wire release. Further, the use of the laser speed meter can accurately measure the length of the wire to achieve an effect of releasing the wire according to a required length, eliminates a wire tightening step in a traditional wire-releasing process, greatly shortens the working time and improves construction efficiency.