Abstract: In the present paper the forced vibrations o'f the two-layer piezoceramic and metal composite thin circular plate with different diameter for the layers, excited with the voltage or uniform pressure, are analysed. The exact solutions and the equations of series and parallel resouance frequencies for simply supported and edge clamped are obtained. The approximate solution forced vibrations, excited with voltage, and the equation of series resonance frequency for the simply supported are given by Rayleigh-Eitz method. The numerical results show that there are optimal values of non-dimesional geomitric parameters for maximal coupling factor. The effect of the elastic and inertia coupling on the resonance frequency is also discussed.