Abstract: A method of lens jacket based on image processing is presented, which can reduce the eccentricity of lens effectively. Based on the features of the lens to be jacketed, the parameters of the optical path are calculated. An area array CMOS device is used to get the reflected cross image from the lens. By using image processing methods to get the eccentricity value, the position of the lens is adjusted to reach the tolerance and the jacket is machined. The testing setup, the motor control system and the software are described. The experiment result shows the method is effective in reducing eccentric error.