The invention discloses a plug pin for axially fixing a pin shaft. The plug pin for axially fixing the pin shaft is characterized in that an axial fixing device is an iron wire formed in a bent mode, a semicircle R is arranged in the middle of the axial fixing device, and the outer diameter of the semicircle R is the same as that of the pin shaft needing to be fixed. Different from a traditional fixing mode that a tool is needed for detachment, the plug pin for axially fixing the pin shaft does not need a special tool, a user can directly grasp a handle by hand and enables an opening to align at a small hole in the pin shaft, the portable plug pin is squeezed open and is inserted smoothly, and under the action of the tension of the portable plug pin, a fixing pin shaft circle clamps the pin shaft tightly to achieve the axial fixation of the pin shaft. The plug pin for axially fixing the pin shaft is quite simple, convenient and rapid to use.