Abstract: The location marking system of digital flat-panel X-ray testing was introduced. This set of markers was made up of 4 unit components, the real-time imaging digital flat-panel X-ray, the software defect positioning, system conversion control and automatic injection devices aiming at positioning unit. The system worked as four steps, such as imaging defect inspection, defect positioning software, controlling information transmission, driving hardware device to aim at the defect point which was detected, jetting pigment attached to the workpiece to conduct accurate positioning mark. The designed system had advantages of simple structure, small space, accurate location, small marking point and popular usage, so it could widely used at the defect location and marking field of nondestructive testing.