The propagation velocity of elastic waves in a ferromagnetic material varies not only with stress but also with magnetization, which is called the magnetoacoustic effect. This effect is the basic principle of magnetoacoustoelastic method. Although magnetoacoustoelastic method can theoretically evaluate stress more precisely than conventional acoustoelastic methods, there has been no application of magnetoacoustoelastic methods to biaxial stress evaluation of plates. In this study, we developed a magnetoacoustic effect measurement system that can transmit and receive surface SH waves while applying biaxial compressive stress with an arbitrary directional magnetic field to a plate. Then, we measured basic data on a nickel with a pronounced magnetoacoustic effect and discussed the usefulness of magnetoacoustoelastic method for biaxial stress evaluation of plates.