In the sheet metal forming area, FE simulation technique to optimize forming process is widely used. To achieve high accuracy FE simulation results, identification of material properties and deformation characteristic such as yield criterion are very important. In this study, to characterize the behavior of plastic deformation for anisotropic material sheets, biaxial tensile tests with cruciform specimen were performed until the specimen was breakdown using biaxial tensile test equipment. The experimental results for yield locus are compared with several theoretical predictions such as von Mises, Hill, Logan-Hosford, and Salat models. Also, the experimental results for yield locus are compared with new yield function which was proposed in this study. The new yield function can describe not only the anisotropic of but also asymmetry behavior between tension and compression, where the material constants of yield function are determined by curve fitting using MATLAB programming.