Femoral head avascular necrosis after femoral intertrochanteric fractures is extremely rare. A case of avascular necrosis of the femoral head was reported at 18 months after intertrochanteric fractures operation, and hip replacement was performed 2 years after surgery. We considered that this case was a typical fracture line close to the base of neck , which damaged the blood supply of retinacular vessels in joint capsule, then caused necrosis of the femoral head. Addressing the high-risk factors such as comminuted fractures and large displacement fractures caused by high-energy injuries, types of fractures near the femoral neck base, excessive external rotation deformity, improper intramedullary nail insertion points, and rough intraoperative procedures，we need to avoid excessive external rotation, overstretching, and rough manipulating. Anatomical reduction should be performed during the operation, the nail entry point should be accurate and avoid repeated drilling.