Idiopathic femoral head necrosis, also known as ischemic femoral head necrosis, is a common disease. The etiology of femoral head necrosis is diverse, but its common pathological mechanism is bone tissue ischemia, so the theory about the pathogenesis, blood supply obstruction, is most easily accepted. This theory believes that the reduction of nutritive blood flow to bone tissue, compression of the intraosseous vascular network or obstruction of outflow veins due to various intra- and extraosseous pathogenic factors cause local blood supply obstruction, which can cause ischemic necrosis of bone tissue in severe cases. The key to the treatment of idiopathic femoral head necrosis is early diagnosis and early treatment to promote local vascular regeneration and restore normal circulation to prevent joint surface collapse. The preventive care of idiopathic femoral head necrosis is very important for health, the following is the preventive care measures of idiopathic femoral head necrosis. 1, crowd prevention In production activities and daily life, pay attention to avoid serious trauma and cumulative stress injuries, such as heavy sports training, excessive long-distance running, etc. Involved in aviation or deep water operations and other workers, should strictly master the operating procedures to prevent decompression sickness caused by osteonecrosis. Those who are frequently exposed to or apply radioactive substances in the fields of national defense, industry, and medicine should strengthen the management of radioactive substances and protective facilities for buildings and individuals. Clinical patients who must apply adrenocortical steroids or indomethacin-like drugs for treatment should strictly grasp the indications and principles of drug use, dose, do not abuse and regular pelvic film. 2, individual prevention (1) primary prevention: create a good biomechanical environment, avoid excessive stress concentration, excessive intensity of activities. The workload and work rhythm should be controlled appropriately for work with high activity and labor load, and pay attention to the combination of work and rest to eliminate or reduce the restrictive pressure on the epiphysis. Strengthen the protection against radioactive substances and radiation, and pay attention to the principles of medication against adrenocortical steroids and indomethacin. (2) Secondary prevention: The early diagnosis of femoral head epiphyseal necrosis can be made based on mild pain in the hip, small ossification center, uneven epiphyseal density, sclerotic cystic changes, etc., and widening of the medial gap of the hip joint on X-ray films. The affected limb should be traction in abduction and internal rotation position or abduction brace to maintain 40?abduction and mild internal rotation position, or plaster fixation to make the femoral head epiphysis incorporated into the acetabulum. For early stage patients with hip pain and flexion deformity, avoid weight-bearing and use hyperbaric oxygen therapy, and operate early if the symptoms are obvious. The affected limb can be traction, and when the pain disappears, it can be protected with a brace. (3) Tertiary prevention: epiphyseal drilling is commonly used in the first stage of aseptic necrosis of the femoral head to promote reconstruction of the necrotic epiphysis by decompression; in the second and third stages, synovectomy or total resection plus drilling of the femoral head or simultaneous implantation of blood vessels are commonly used, and in recent years, fetal cartilage implantation has also been reported to achieve better results in repairing aseptic necrosis of the femoral head. Salter’s pelvic osteotomy is feasible in cases of total femoral head epiphysis involvement and subluxation, and sometimes pelvic osteotomy is performed together with subtrochanteric rotational osteotomy, after which the femoral head is fixed with a hip “human” cast for 2 to 3 months, so that the femoral head is better covered.