We discuss preferential, perpendicular acceleration of &agr; particles in large amplitude magnetohydrodynamic (MHD) waves by using a test particle simulation. In a 3 component plasma that consists of electrons, protons and &agr; particles, one of the wave branches has phase velocity larger than the Alfv¿n velocity in a long wave length regime. We find that the wave-particle interaction between this wave and the other Alfv¿n wave leads to strong anisotropic acceleration in perpendicular direction to the ambient magnetic field. We examine the wave-particle interaction for a 3 component plasma, and obtain good agreement with the test particle simulation. ¿ 2001 American Geophysical Union