Inverse analysis is a method for determining material parameters by minimizing the difference between experimental and the finite element (FE) simulated results, such as the load-stroke curve and barreling shape of a deformed specimen using an optimum design technique. In this study, ring compression tests were conducted to predict the flow stress of materials and interfacial friction conditions. Cylinder compression tests were conducted under the same process conditions to estimate the validity of the data obtained from the ring compression tests. By comparing the experimental results with the FE simulated results, it was confirmed that flow stress and the interfacial friction condition obtained from the ring compression tests, as well as their inverse analysis, are quite reasonable. The validity of both the flow stress function and the interfacial friction condition using the above procedures was verified by the experiments.