Abstract: Aiming at the low processing efficiency and poor forming quality of the upper lug of ultrahigh-strength steel products, in this paper, lugs with materials of DT300, 30CrMnSiNi2A, 45 and 17-4PH are respectively processed on ultrahigh-strength steel products through the laser additive manufacturing technology. Then in order to study the forming of lug bottoms, magnetic particle inspections are conducted on the interfaces of lug bottoms before heat treatment, after heat treatment and after finish machining respectively. Furthermore, X-ray fault detection is performed on test pieces processed by laser additive manufacturing technology so as to research the internal forming. The final results demonstrate that lugs processed by materials of DT300, 30CrMnSiNi2A and 17-4PH are of better forming quality without obvious internal defects; while lugs of material 45 are inferior in forming quality with obvious cracks in lug bottoms and intensive internal air-holes. Through the research and analysis, a new idea and method for processing of the upper lug of ultrahigh-strength steel products is put forward, and the theoretical basis and research methods are provided for processing of the same type of products.