The invention discloses an opening type intramedullary nail which comprises a nail member and a center-pole, wherein the nail member is in hollow pipe shape and includes a far-end and a near-end, the nail member is provided with a pinning aperture equipped with a pin, the center-pole includes a far end and a near end, the center-pole is arranged in the hollow pipe of the nail member in a movable manner, the pipe wall of the nail member far-end is provided with expansion slots longitudinally, the far end of the center-pole is provided with an expansion head, the maximum outside diameter of the expansion head is larger than the internal diameter of the pipeline section where the expansion slot is located, the near end of the center-pole is located at the near-end of the nail member, and the expansion head is connected with the center-pole to form a union body for synchronous rotation and moving, the near head section of the center-pole is equipped with a screw-threaded axial draught device. |