The X-ray manifestation of ischemic necrosis of the femoral head is divided into four stages: In the first stage, although there is pain in the hip or knee joint, there are no obvious changes on the X-ray. In the second stage, the X-ray changes can appear as a partial cystic change. In the third stage, there is basically a collapse of the femoral head. In the fourth stage, there will be changes in the acetabulum. At this time, the X-ray shows mainly the narrowing of the gap of the hip joint, and in addition to the collapse of the femoral head, there will be degenerative changes in the acetabulum, and sometimes there will be cystic changes in the acetabulum.