Abstract: This paper investigates the propagation behaviors of air gas waves between a homogenous magneto-electro-elastic (MEE) half-space and a functionally graded MEE layer. The properties of functionally graded magneto-electro-elastic plate are assumed to vary exponentially in the direction of the thickness, and the surface is mechanically free and subjected to two kinds of electromagnetic boundary conditions. The dispersion equations are derived, and the numerical examples are provided to show the influences of graded variation, layer thickness and the electromagnetic boundary conditions on the phase velocity. The obtained results are of significance for the applications of functionally graded MEE materials to acoustic wave devices.