Typical application of piezoelectric materials was used in active flutter suppression of a swept-back cantilevered composite laminate plate. The structures containing distributed piezoelectric sensors and actuators have self-monitoring and control capabilities due to the direct/converse piezoelectric effect. A generalized finite element formulation was derived for modeling the electromechanical coupling system. The doublet lattice method was used to model the unsteady aerodynamic loads acting on the lifting surface. Modal transformation and Roger approximation were involved to develop the equation of motion in state-space. LQG controller based on multi-input multi-output system was designed. The flutter characteristic of the closed-loop system was compared with the open-loop system by stability analysis. The flutter suppression results were presented in the time domain using the Runge-Kutta method. Numerical simulations demonstrate the effectiveness of the above methods.