Abstract: The distortion of grating head-up display seriously affects the observation, measurement, positioning and analysis of object. Therefore its distortion quantitative measurement must be finished during the process of setting and assembling. Combining with the work principle and distortion causes of grating head-up display and utilizing the photoelectric measurement technology, its distortion quantitative measurement was further studied. Firstly, the distortion measurement system was set up to measure the distortion of grating head-up display caused by different reasons, and its CCD detector was calibrated. Secondly, the calibrated CCD detector was used to measure the distortion of grating head-up display, and the uncertainty of distortion measurement was analyzed. Utilizing this distortion measurement system, the experimental results show that the uncertainty of the relative distortion measurement of grating head-up display is 0.5%.