In this paper, a new method for reconstructing the model of the necrotic femoral head is presented. It can reconstruct the optimal femoral head prosthesis model utilizing the reverse technology. This new method not only affords a theoretical model for the accurate operation position fixing in orthopaedic clinic, but also provides an innovative practical means for the individualized manufacturing of artificial femoral head prosthesis.The femoral head is regarded as a sphere. Then, the femoral head's configuration is reconstructed by means of fitting using the data points on the unspoiled acetabulum lunate surface. A spatial dynamic analysis is implemented, it is proved that the sphere fitting model can well satisfy the spatial motion relation between the femoral head and the acetabulum. The experiment results show that this method can well reconstruct the femoral head model of the target patient.