The laser scanning technology was developed rapidly in recent years to fulfill the great needs of high speed, high quality image and documentation transmission and retrieval especially for facsimile and computer input/output applications. The main components of a laser scanner include a laser source, modulator, and a deflector. Recently,semiconductor lasers which can be directly modulated become popular. The modulator used externally thus can be eliminated. Among several different deflection devices, the rotating polygon mirror is used most popularly because it has high speed, large deflection angle, and low cost. Ideally, each facet of a polygon mirror should be parallel to the rotating axis to produce uniform scanning lines. However due to the fabrication limitation, it is very difficult to have perfect parallelism of each facet. The tilt of the facet will displace the scanning lines to yield a periodical pattern to which the human eyes are very sensitive. Many researchers reported several methods such as tightening the tolerance of the polygon mirror, using cylindrical lens, and employing optical-acoustic device to eliminate the wobble error. This paper will report a new method which employs a piezo-electric device to achieve the above mentioned purpose. We use an optical sensor to detect the displacement of the dislocated scanning line and feed the information to a piezo-electric device with a mirror to compensate the wobble error. This paper will describe the method briefly and present the theoretical calculation and experimental results.