The invention provides an aluminum alloy section bar for a rail traffic vehicle body top cover edge beam and a fabrication method for the aluminum alloy section bar and relates to the technical fieldof aluminum alloy section bar preparation. The aluminum alloy section bar for the rail traffic vehicle body top cover edge beam is in a long strip shape and internally provided with a plurality of cavities in the length direction, the section perpendicular to the length direction of the aluminum alloy section bar is in a reverse T shape, and one side face of the aluminum alloy section bar is provided with two stretching-out small claws, the bottom face of the aluminum alloy section bar is provided with one hanging arm, the aluminum alloy section bar for the rail traffic vehicle body top coveredge beam is qualified in profile size and good in uniformity and stability, and all mechanical properties of the aluminum alloy section bar for the rail traffic vehicle body top cover edge beam meetthe requirements. The fabrication method for the aluminum alloy section bar for the rail traffic vehicle body top cover edge beam comprises the following steps of melting refining, casting, homogenizing annealing, testing, cast bar heating, mold and extrusion tube heating, extruding, on-line quenching, stretching straightening, saw cutting and size testing, artificial aging, final testing and packaging, by means of the fabrication method, all parameters in the technology step process are strictly controlled, mass production of qualified products can be performed, the rejection rate is low, andthe production efficiency is high.