Abstract: It's assumed that the rotor blade and nacelle were of a rigid body and the wing was represented by an elastic beam,the blade pitch/flap/lag structural coupling and pitch/gimbal coupling were considered,and then,tilt-rotor/wing dynamic equations were founded on the inertial coordinate frame according to Newton's Second law and finite element method.These two dynamic equations were coupled through the common degrees of freedom between the rotor hub and the nacelle/wing system,and then the tilt-rotor/nacelle/wing coupled system aeroelastic stability model of a full-hinged tilt-rotor during cruise flight was acquired.The rotor aerodynamic model was based on the improved element-momentum theory,with consideration of the velocity's unsteady aerodynamic influence of perturbation parts.The calculation shows that the model is correct.