Abstract: According the extensive theory oif flexual vibration of composite plate system in the last paper, the vibration and scattering sound field for a rectangular elastic-viscoelastic composite plate with its edges simply-supported are under study. The deflection of the composite plate is expanded into a series of normal mode terms, Whatever plate is vibrating in water under influence of incident sound wave. Interaction between normal modes owing to sound medium coupling is taken into consideration. As a function of kL₁, r; m, n; p, q （k is wave number, L₁ is length of one parallel edges, r=L₂/L₁ is parametric variable, L₂ is length of another parallel edges）, the coupling coefficients between （m, n）; （p, q） modes of vibration are calculated numerically, with which the sound irradiation and the vibration of the composite plate may be characterized. And then, amplitudes of normal modes of flexual vibration for a steel-rubber bilaminlair plate in sound field, are calculated also.
Further, the irradiation, sound field pressure at the different point near by the surface of bilaminar plate are. calculated numerically, The results calculated hereby are coincident qualitatively with the experimental.