Abstract: For the under-actuated characteristics of bird-like flapping wing air vehicle(ornithopter),a method is presented to simplify the vehicle flight control problem and realize locally asymptotic stabilization.Dynamics and kinematics models of the ornithopter are established and analyzed firstly,proving that the ornithopter control problem is equivalent to the attitude control problem under the circumstance that the lift and thrust are independently controllable.Further analysis indicates that lift and thrust of the ornithopter are both independently controllable,so the attitude control problem of the ornithopter corresponds to that of a rigid body with coupled inputs.Locally asymptotic stability is achieved with the designed smooth time-varying feedback control law,then the flight control problem of the ornithopter is solved.