Abstract: Specimen reconstitution technology is important for the in-service safety of reactor pressure vessels (RPVs) in nuclear power plants. To verify the feasibility of electron beam welding for the restructured specimens, the electron beam welding to restructure the 16MND5, 10Cr12Ni3Mo2VN, and X6NiCrTiMoVB 25-15-2 Charpy impact specimens for three kinds of steels was adopted, the microstructure and mechanical properties of the restructured specimens were characterized, and the Vickers hardness and impact toughness of the specimens were tested by non-destructive flaw detection, optical microscopy, and scanning electron microscopy. The results show that the microstructure of these three steels in weld zone is relatively dense, and no obvious crack defects occur. The welding quality of 10Cr12Ni3Mo2VN restructured specimens is the best, and the mechanical properties are relatively close to those of the original specimens, demonstrating that the electron beam welding has the good application potential of reconstitution in nuclear power field.