The invention discloses a fixture for steel rail forging, and belongs to the field of mechanical equipment. The fixture is provided with transverse and longitudinal motion platforms and a liftable device for realizing three-dimensional motion of a steel rail in all directions, and meanwhile, is provided with a rotating disc for realizing large-angle rotation of the steel rail. The invention further discloses a steel rail forging device adopting the fixture; and the device comprises a medium-frequency heating furnace, forging equipment and an infrared distance measurer, realizes full-automatic forging of the steel rail, and improves the machining efficiency. Meanwhile, the invention further discloses a steel rail heat treatment system adopting the forging device; and the system comprises a conveying platform, air cooling equipment, a normalizing furnace and a pushing table, and can further reduce machining procedures, reduce the energy consumption and improve the machining efficiency. In addition, the invention discloses a steel rail heat treatment process according to the system; and the process comprises a forging process and a quenching process, and can realize thorough hardening of a rail head and uniform quality in machining of the steel rail.