The present invention discloses a construction method for a locating bracket of a tunnel anchorage prestressed system, comprising the following steps: manufacturing locating bracket racks outside a tunnel, assembling the racks into segmented locating bracket steel trusses, and installing rolling wheels at the bottoms of the trusses, and temporarily fixing prestressed pipes on the trusses; laying a slip track at the bottom of the interior of the tunnel, putting the steel trusses onto the slip track through hoisting in a segmented manner, and slowly lowering the steel truss by a winch; when the steel truss slides to the design positions, removing the rolling wheels from the steel truss for sliding of the next segment of section truss; and adjusting and fixing the positions of the steel trusses and the prestressed pipes. Through the method, the prestressed locating bracket is subjected to assembly construction, the process is simple and the project progress is fast, accordingly the construction period is greatly shortened, construction costs are reduced, and the economic efficiency is very obvious.