For additional functionality of artificial knee joint, the kinematics of knee has been evaluated using 2D/3D image registration technique after total knee arthroplasty. To evaluate the knee kinematics of implant, it is important how to adjust the ligament balancing around knee joint during surgery. In the kinematics evaluation of image matching, it is difficult to feed back the ligament balancing of knee because the information from image matching will be available after surgery only. Therefore, we developed a CT-based navigation system with the function of measurement of knee motion during surgery, which has been normally applied to enhance the accuracy of implant setting for target bone. The kinematics of knee has been evaluated with position of implant setting and ligament balancing which were obtained by this system during surgical operation. As a result, (1) The knee kinematics showed different trends between bone and implant based coordinate system, (2) Increasing 2mm thickness of insert between femoral and tibia component of artificial knee joint, the anterior-posterior shift of implant with knee flexion was decreased by changing the ligament tension around knee joint. In conclusion, it is possible to measure the knee kinematics with consideration of ligament balancing using the developed navigation system during surgery.