Construction method for cast-in-place steel truss girder support of high-altitude large-span upper cross beam of cable bent tower

The invention discloses a construction method of a cable bent tower high-altitude large-span upper cross beam cast-in-place steel truss girder support. The construction method comprises the following steps that firstly, a steel corbel reserved notch and a steel corbel pull rod pre-buried pipeline are constructed; step 2, processing the steel member; welding a steel truss hoisting unit; 3, a steel corbel reserved notch and a steel corbel pull rod embedded pipeline are cleaned; 4, installing a side fulcrum supporting system; 5, longitudinal distribution beams are installed, and a lower sliding face is arranged; 6, the steel truss girder support is hoisted in place, and an upper sliding face is arranged; step 7, performing concrete pouring construction and equal strength on the upper cross beam; step 8, carrying out falling operation on the steel truss girder support; ninthly, the steel truss girder support slides and is dismantled; and 10, the steel corbels are dismantled, and notches are reserved in the steel