The purpose of this paper was using a new design method to build the prosthesis of total knee replacements (TKRs) .The femoral component was created with fewer design parameters, which is closer to natural articular surface.Elliptical curves were proposed and generated to fit the sagittal profiles of femoral condyle.Models 1, 2, 3 were defined as the twist angle of lateral condyle surfaceφ =0° , 10° , 20° respectively.According to the gait cycle data, femoral and tibial component models were placed in anteroposterior or rotation about the neutral position in the three-dimensional modeling software.With a small rotation about the tibial axis (± 3° ) , an overlapped volume was intersected from models.The stability of knee implant models was evaluated on the magnitude of overlapped volume.During the gait cycle (flexion angel from 0° to 58° ) , the overlapped volume of model 1 was decreased gradually from 122 to 54.9 mm3 (model 2 was from 131.9 to 34.5 mm3, and model 3 from 216.5 to 58.8 mm3) .These newly designed femoral components provided enough stability in lower flexion angle, while provided flexibility in conditions of high flexion.