Abstract: Due to the center of gravity varying over a specified range, the aircraft may deviate from its known dynamics, thus bringing special problems to the attitude control system. A synthesis approach based on in-flight estimation of center of gravity position and the inverse dynamics was proposed. First of all, a six degree-of-freedom flight dynamics model of aircraft with center of gravity offset was built. Based on the above model, the inverse dynamics in analytical form was obtained by deducting the dynamic equation. The estimation of center of gravity location could be obtained by the initial and updated weight data. As in-flight estimation of the center of gravity position could be utilized effectively, the simulation results demonstrate good control performance under various possible conditions of center of gravity offset. The proposed method is also clear and easy to implement.