The invention relates to a shaft part extrusion forming die which comprises a male die and a female die, wherein the male die has a split type structure and comprises a fixed part and a movable part; a fixed end is arranged on the fixed part; connection parts are respectively arranged on the fixed part and the movable part. The invention also relates to an extrusion forming method for extruding a shaft part by using the extrusion forming die. The extrusion forming method comprises the steps of 1) putting a blank into the female die, putting the movable part on the upper end face of the blank, and enabling a press to drive the fixed part to move downwards and push the movable part to extrude the blank; 2) after the extrusion is finished, enabling the press to drive the fixed part to return, eject the movable part and a workpiece and implement demolding or enabling the press to drive the fixed part to move upwards until the workpiece is separated from the fixed part and to drive the fixed part to move in parallel to one side on which the fixed part is staggered from the movable part, eject the movable part and the workpiece and implement the demolding. The shaft part extrusion forming die and the extrusion forming method which are disclosed by the invention can realize extrusion forming of long shaft parts and reduce the equipment investment for long shaft part extrusion forming.