The invention relates to a method for laying a large cable on a small tray of an overhead cable bridge. The method includes the following steps that (1) preparation is made before laying is conducted; (2) the cable enters an overhead window through a cable climb roll frame; (3) the cable achieves steering through a deflecting pulley; (4) the cable penetrates through a short pulley; (5) the cable bypasses the deflecting pulley and achieves steering; (6) the cable makes a turn by penetrating through a pulley row; (7) the cable penetrates through a forward and reverse pulley and climbs a slope; (8) an internal angle horizontal frame is additionally arranged at the 90-degree horizontal turning position of the narrow overhead cable bridge, and a set of temporary resultant force stay wires is additionally arranged on the external angle resultant force side of the overhead bridge; (9) the cable penetrates through the deflecting pulley and achieves steering. The method for laying the large cable on the small tray of the overhead cable bridge is reasonable in design, high in pertinence and capable of conducting construction according to the basic requirements of the regulations and the standards. By the adoption of the method, the construction quality of the cable can be guaranteed, the construction progress can be accelerated, and the construction work can be finished perfectly.