The objective of the project is to simulate the mechanical properties of knee joint numerically, to propose basis theory and optimal design for the prosthesis replacement operation. The major research work of the project focus on the following aspects: establish real 3-D finite element knee joint model based on anatomy (including ligaments, meniscus, patella etc.); associated with finite element contact analysis, dynamic simulation, parametric finite element modeling, to simulate the mechanical properties of knee joint in movement and surgery numerically, to research the injury mechanism of ligament, meniscus, patella etc in human movement, furthermore compare the advantage and disadvantage of some surgery procedures; to optimize the knee replacement surgery, including the choice of prosthesis, the angle of insert, the treatment of PCL and patella etc.