Abstract: In order to improve the parallax measurement accuracy of the head-up display (HUD), a new method based on the computer vision, CCD and digital image processing technology is put forward based on the analysis of various traditional measurements. The principle was discussed and formulas were deduced. The design of the optical system was performed, and the method of image processing was investigated. This method adopts CCD instead of the subjective interpretation, thus the measuement accuracy of parallax is within 30″. The new method is not only fast and accurate, but also straightford and qunatilized. The alignment accuracy and efficiency of HUDs are improved greatly.