In order to meet market demand and to advance technical capability in flexible printed circuit board (FPC), MMSL (Mechanical and Mechatronics Systems Research Laboratories) develops a circuit defect marking system with artificial intelligence to improve domestic FPC quality and to add product values. The artificial intelligent defect marking system involves various technologies, such as defect identification technology, defect positioning technology, and laser marking with robotic arm. The system can effectively reduce labor cost, minimize inspection errors, and improve yield. The technology can also be applied in other advanced electronic devices such as flat panel display and semiconductor industry, etc. In this article, the artificial intelligent defect marking system for fine-line flexible printed circuit board will be reviewed and discussed in depth.