The invention relates to a distal automatic cutting bone core extraction device which belongs to the technical field of orthopedic surgical equipment, and is used for complete extraction of a bone core with the length being multiple times of diameter length of the bone core, and the technical scheme is as follows: the device comprises a positioning needle, a soft tissue separator, a positioning sleeve, a path-opening trephine, a cutting trephine and a drillstock, wherein the path-opening trephine and the cutting trephine are cylinders, cutting teeth are circumferentially arranged on the upper edge of the end surface of the wall of the distal cylinder, two pin holes are arranged on the wall of the proximal cylinder, the path-opening trephine cylinder and the cutting trephine cylinder have the same inner diameter and the same outer diameter, cutting-off teeth which are arranged obliquely are fixedly arranged on the inner wall at the lower end of the cutting trephine, and scales along the direction of a long shaft are arranged on the surface of the outer wall of each cylinder. By utilizing the device, the difficult problem that the bone core with the length being a plurality of times or even more than ten times larger than the diameter can not be extracted completely at the distal end in an orthopedic surgery is solved, thereby having the ground-breaking significance; and the device is mainly used for extracting the bone core with complete shape from a thick bone block through a blind hole, and especially applicable to extracting the bone cones with femur proximal or distal expansion parts and tibia proximal expansion parts.