A biodegradable pure magnesium bone nail comprises a rod-shaped pure magnesium screw bone nail (1). From the bottom of a crossed groove (4), for turning a screw, of a tip of the screw bone nail (1), an axial hole (2) whose length is 2/3 of that of a rod of the screw bone nail is manufactured. In the length of the axial hole (2) of the screw bone nail (1), several radial holes (3) are uniformly manufactured from the bottom of thread into the axial hole (2) at 90 degrees.
