The invention discloses a gear shaft product forge piece. The gear shaft product forge piece comprises an end head portion, a rod portion and a conical portion which are integrally formed by a cylindrical bar, and the end head portion, the rod portion and the conical portion are located in the same axis from top to bottom. In the preforging stage, the cylindrical end head portion and the cylindrical rod portion are in conical face transition, and are in a circular bead shape after being subjected to upset extruding. In this way, by means of the gear shaft product forge piece and a machining process of the gear shaft product forge piece, the gear forge piece can be forged and formed through one-time heating, the metal flow line of the forge piece is improved, the internal and surface quality of the forge piece is improved, machining allowance is reduced, and the material utilization rate of the forge piece is improved.