Biomechanics is an important scientific foundation of physical therapy and is used to relate kinematics, kinetics, statics and dynamics for comprehencing human movement. The knee is well studied for demonstrating biomechanical analyses of joint because of its simplicity. The purposes of this study were 1)to provide categories and concepts of biomechanics, 2) to apply these concepts to knee movement involving daily living and gait, and 3) to review current and preceeding researches about biomechanics of knee. Thus, physical therapiestes in clinic may be helped understand of movement which includes considerations of description and production related force, moment and power.