Abstract: In this papas two kinds of elements,triangular laminated plate element with nine degree of freedom based on multi-variable quasi-conforming and penalty element technigue and laminated beam element with six degree of freedom are presented.Effects of transverrse shear deformation and rotational inertia are considered in these two elements.Free vibration, damping charactristic and transient response of stiffened composite plate are investigated by using finite clemenl method.Results obtainod are. valuable for the designs of stiffened composite,plates.