Disclosed therein is a big femoral head and femoral head surface replacement, which are used for hip osteoarthritis and vascular necrosis of femoral head. As a person get older and aged, the weight bearing hip joint is indispensably changed to osteoarthritis and sometimes showed avascular necrosis of the femoral head with unknown etiology. The deformed femoral head and hip joint should be replaced with the THA. Till now, the total hip replacement is performed in such a way that the necrosed femoral head and a healthy femoral neck are all removed and a femoral stem is inserted into the marrow cavity, and in this case, a small femoral head causes a reduction of a range of motion and dislocation of the hip joint occasionally, and osteolysis due to abrasion of plastic acetabular liner. In case of a conventional femoral head surface replacement (hereinafter, called "conventional FHSR"), a complication of femoral neck fracture and could not combined use with conventional THA. Recently, hard bearing system such as metal on metal THA or ceramic on ceramic THA without using plastic has been introduced to solve the problem of osteolysis due to abraded plastic particles generated when the THA is worn out as time goes. But there also have many problems as a limited range of motion, resected normal femoral neck and difficulties of rereplacement of the femoral stem. Because of the big femoral head or the FHSR can increase the range of motion and lower dislocation rate these devices are gradually widespread in young active person and Asian peoples. This invented design of the modularity gives the convenience to the surgeon and economically lower burden to patients to use of the FHSR and big femoral head system. The related accessory showed initial stability of the FHSR during operation and prevent from femoral neck fracture in follow-up periods.