Abstract: Aiming at the micro defects such as surfacial and internal pores and cracks of steel structure of industrial heritage, a computed tomography (CT) system was developed for three-dimensional visualization to detect the defective position. Then laser remanufacturing technology was used to accurately repair the defect position with Fe-Cr-Mo+8wt%Al₂O₃ composite powders. The results show that the surface cracks and pores of the sample are significantly reduced after laser repair. The repair layer are mainly composed of solid solution FeCr phase, carbides M(Fe, Cr, Mo)₇C₃, intermetallic compound Fe₃Al and ceramic phase Al₂O₃, and it significantly improves the corrosion resistance.