Since the age of onset of patients with femoral head necrosis is relatively young, averaging 20 to 50 years, early diagnosis and treatment of the disease is crucial, and the longer the disease progresses, the worse the outcome of the disease. Patients with bilateral femoral head necrosis usually develop symptoms on one side first due to the different rates of progression of the lesions on both sides, but about 72% of patients develop symptoms on both sides within two years. Excluding patients with lupus erythematosus, the ratio of men to women is 7/3. The disease is insidious and has no specific signs and symptoms. Poorly localized vague pain around the hip joint, often in the lower pelvis, inner thighs and buttocks, are helpful for early diagnosis. With imaging, the physician hopes to obtain information on (1) whether the necrotic area is collapsed; (2) the size and localization of the necrotic segment; (3) for a collapsed femoral head, to assess the degree of femoral head compression; and (4) to obtain imaging evidence of whether there is coexisting acetabular osteoarthritis, and thus to make a diagnosis of a staged femoral head necrosis. There are more staging methods for femoral head necrosis, we propose a comprehensive staging method based on long-term clinical observation and clinical, X-ray, CT, ECT, MRI, etc. This method can detect suspicious cases at an early stage and is helpful to guide the selection of clinical treatment plan and the estimation of disease prognosis. Symptoms and imaging performance of femoral head necrosis stage I Progressive pain in hip and knee joint, mild restriction of hip joint activity, X-ray performance, normal appearance of femoral head, slightly blurred cartilage and trabecular structure, or speckled osteoporosis, CT, mild thickening of trabecular bone in the middle of femoral head, stellate structure, radial or or pseudopod-like branching arrangement to the cartilage part of femoral head, some small cystic changes visible in the subchondral area. ECT has early concentration, low arterial blood supply, and MRI shows low signal and abnormal changes. The symptoms and imaging manifestations of femoral head necrosis stage II are mainly hip pain, mild limitation of abduction and internal rotation, X-ray manifestation of subchondral cystic changes, destruction and loosening of bone tissue, also visible in the cartilage area half-moon translucent area, called “crescent sign”, CT can be seen in the subchondral bone marrow cavity part of the bone trabecular sclerosis changes. The subchondral bone marrow cavity is more than 0.5 cm cystic lesions, and ECT shows a large “hot zone” (depressed blood) or a large “cold zone” (ischemia) in the resting phase, and there is an intermediate phase of hot and cold intermingling, and MRI, a large low signal area. Symptoms and imaging manifestations of femoral head necrosis stage III: increased hip and knee pain, decreased weight-bearing endurance, claudication; X-ray shows subchondral microfractures, partial interruption of trabecular continuity, collapse and flattening of the weight-bearing area above the femoral head or fragmented bone fragments under the cartilage; CT shows disorganized trabeculae in the femoral head, enlarged cystic zone, bone fragmentation, deformation of the femoral head, hyperplasia and sclerosis in some areas, and osteophytes in the acetabulum; ECT and MRI are more obvious than stage II. Symptoms and imaging manifestations of femoral head necrosis stage IV Restriction of hip joint movement, difficulty in walking in severe cases, or loss of labor ability, X-ray manifests joint space narrowing, flattening and collapsing deformity of femoral head, hyperplasia and deformation of acetabular rim, osteoarthritic changes, CT shows deformation of femoral head contour, joint space narrowing, intermingling of femoral head sclerosis and cystic changes, fragmentation of bone structure, etc. ECT shows local concentration at the head of the socket ECT showed localized concentration at the intersection of the socket head, reduced slope of the blood pool phase, and MRI low signal area was more obvious than stage IIIII.