Intramedullary nailing is a typical surgical operation to repair fractures of long bones. Several magnetic position method can find both positioning and directional guidance. However, current approach needs to place an internal position magnet at the screw hole, and the magnet cannot be removed after operation. This paper presents the prototype of a removable mechanism to remove the position magnet from the nail without modifying the intramedullary nail, as well as the improvement on the position system for this new design.