Abstract: As an important branch of metal additive manufacturing, laser repair technology is one of the core technologies in strategic emerging industries such as equipment remanufacturing. It has been popularized and applied in key fields such as aerospace and defense equipment. The results show that the evolution of stress and strain fields is closely related to the defect distribution and geometry of laser repaired components, which is key to determine the repair quality. The on-line measurement and characterization of relevant parameters is an important issue attracting widespread concern in industry and academia, however, due to the complexity of the laser repair process and the harsh measurement environment, traditional inspection methods and techniques are difficult to be directly applied to laser repair engineering, so it is urgent to develop new detection techniques suitable for repair engineering. At present, there is still a shortage of in-situ monitoring tools to match the laser repair process. In this paper, we investigate and analyze the key issues in laser repair, the advantages and challenges of commonly used inspection techniques, and give an outlook, which could provide a useful reference for the research of laser repair process.