Abstract: Objective To address the long-standing import dependency of welding materials for 9Ni steel in liquefied natural gas storage tank, this study comparatively analyzed microstructure and mechanical properties of welded joints with domestically produced and imported ERNiCrMo-4 nickel-based welding wires. Methods Using 20 mm thick 9Ni steel plates and fully automatic TIP-TIG welding process, tensile properties, cryogenic impact toughness, and bending performance of welded joints with domestic Jinchuan (JC) and imported ESAB (ESAB) welding wires were systematically tested. Microstructural analysis revealed mechanisms behind performance differences. Results Results show that the domestic welding wire exhibits superior impurity control (42.27% lower P content). Welded joints achieved a tensile strength of 697 MPa (mean), meeting the requirements of EN 10028-4: 2017 standard (680～820 MPa). At −196 ℃, impact absorbed energy of weld and heat-affected zone reaches 121.3 J and 161.7 J respectively, exceeding that of imported welding wire by 3% and 21%. All bending tests passed qualification. Microanalysis confirms finer grains in HAZ with domestic welding wire, explaining their enhanced cryogenic toughness. Conclusion This study validates domestic ERNiCrMo-4 welding wire as a viable substitute for imported products, advancing the localization of 9Ni steel welding materials.