The invention relates to a spline extrusion manufacturing method. The extrusion manufacturing method adopts an axial forming technology falling into a one-time forming and a pulsed step-by-step forming. The two technologies respectively comprise the following steps: the one-time forming comprises the steps of: 1) pushing a to-be-processed spline part of a workpiece into a first forming die along the axial direction; and 2) performing extrusion forming by the first forming die under external extrusion force, at the same time pulling the workpiece out along the axial direction, and keeping the workpiece away from the first forming die; and the pulsed step-by-step forming consists of the steps of: 1) pushing a to-be-processed spline part of the workpiece into a second forming die along the axial direction; 2) clamping and fixing the workpiece through a clamping device; 3) clamping and fixing the second forming die through a reinforcing steel strip; and 4) conducting extrusion forming by the second forming die under external extrusion force. The method provided by the invention can process some structure products that cannot be realized by cold rolling spline process.