On　the　basis　of　the　nonlinear　elastic　theory　and　piezoelectric　theory,　nonlinear　governing　equations　for　moderately　thick　piezoelectric　laminated　plates　subjected　to　a　parametric　excitation　are　established.　The　incremental　harmonic　balance　method　is　employed　to　search　for　a　solution　for　the　nonlinear　dynamic　stability.　Numerical　simulation　is　also　given　to　reveal　the　influences　of　geometrical　nonlinearity,　transverse　shear　deformation,　control　voltage　and　actuator　thickness　on　the　nonlinear　dynamic　stabilities.　The　inherent　relationship　between　the　coupled　mechanics　and　electricity　is　also　elucidated.