Artificial joint replacement is a feasible approach to serious arthritic diseases. The 3D reconstruction for femur provides scientific basis for the prostheses optimal design. Development of Computed Tomograph makes it possible to obtain the geometry shapes of bone cross sections nondestructively. When the cross sections are arranged in sequence along the bone axis, the 3D image of bone can be developed. By taking the femur for example this paper presents a new 3D reconstruction process of human bone systemly including CT image processing, outline points screening, 3D mesh surface building and image rendering.