To prevent early failure in artificial knee joint, several techniques such as FEM or Sensor Pressure have been used for contact analysis. These methods provided variety results and different agreement with each other. When using FEM, it is crucial to appreciate the accuracy of the numerical model of the artificial knee joint which has intricate geometries with non-uniform contact, and Sensor Pressure can only measure the contact pressure of the articular surface. We investigated contact stress on the newly designed of artificial knee joint using 3D mathematical model. To verify our simulation results, we represented photoelastic method for viewing the overall surface stresses on the tibial insert. We developed the 3D knee model which include not only tibio-femoral joint but also patello-femoral joint. This model could reproduce natural knee movements such as rollback of the femur. In the experimental results, variations of stress pattern using photoelasticity were easily observed in epoxy resin of tibial model using our modified frozen-stress technique. The technique used facilitates stress distribution and a two dimensional view of the stress concentration. Higher stress concentration was always observed on medial side at any angles of knee flexion. At 90º of flexion, stress concentration moved slightly to posterior. Using our 3D model, it was confined to measuring; contact area, contact pressures and checking for misalignment of components, and photoelasticity was employed to visualize critical contact area and contact stresses in different angles of flexion. Based upon this study, suggestions for optimum design of artificial knee joint were presented.