The invention relates to a support for fast and precise positioning of truss nodes of a truss bridge, comprising a truss positioning system, a support fine-tuning system and a support unloading device, the truss positioning system is arranged above the support fine-tuning system, and the support fine-tuning system is arranged on the support unloading device Above; the supporting and unloading device adopts a sulfur sand box; the truss positioning system includes a steel frame and positioning rollers for positioning the truss. The steel frame is composed of a left inclined frame, a right inclined frame, an upper beam, a lower beam, and a left inclined The beam, the right inclined support beam and the vertical beam are connected; the upper beam, the lower beam, the left inclined support beam, the right inclined support beam and the vertical beam are all length-adjustable tie rod beam structures; there are multiple positioning rollers, which are installed separately On the left side inclined frame and the right side inclined frame and arranged up and down in sequence along the corresponding inclined frame; the support fine-tuning system includes a roller mounting steel frame, a plurality of support rollers, prefabricated steel plates and left and right positioning adjustment screws. This support can adapt to different truss constructions.