Aiming at the vibration problem of aircraft skin during the thinning process, the vibration suppression technology for mirror milling of thin-walled parts based on magnetic follow-up support fixture is proposed. Firstly, the frequency response functions and vibration amplitudes of workpiece under different milling conditions are compared and analyzed by using finite element analysis software, principle of the mirror milling vibration suppression technology is determined. On this basis, a new type of magnetic follow-up support fixture is designed. The mathematical model of axial magnetic force considering pitching angle of the fixture is then established to ensure application of the fixture more effectively; dynamic response at the milling point when the balls are not in contact with workpiece is investigated specifically and the optimal support air pressure is determined. Finally, the fixture was manufactured and experiments of aircraft skin milling under different machining parameters were carried out. The experimental results show that when the fixture clamps workpiece with applied support air pressure of 0.1 MPa at the same time, the vibration amplitude of workpiece is significantly reduced, which proves effectiveness of the proposed vibration suppression technology.