Abstract: When small flexible wing aircraft encounter a strong gust, the attitude and the centroid acceleration will change drastically, and the elastic motion of the flexible wing will be induced, which may lead to instability. Flexible wing aircraft gust alleviation system should consider both the rigid and elastic degrees of freedom. The longitudinal state space equation of the flexible wing vehicle under the disturbance of continuous gust and continuous turbulence was deduced. A gust alleviation controller was designed by using the predictive control method,and the control allocation strategy of multiple control surfaces was proposed, which solved the problem of insufficient control ability of the independent control surface under strong gust disturbance. The simulation results show that the model predictive control can effectively reduce the structure load of the aircraft caused by discrete and continuous gust, stabilize the rigid body motion and elastic motion, and its control effect is better than that of LQG control.