In view of the corrosion resistance requirements of our company’s research,design and manufacture of high-sulfur natural gas three-phase separator equipment for a gas field,it is necessary to surfacing Inconel 625 nickel-based alloy on the inner wall of the equipment shell,determine the process plan of using domestic nickel-based alloy electrode electroslag surfacing technology for the inner wall surfacing,and conduct the welding process evaluation.The evaluation results show that the surfacing welding process of domestic nickel-based alloy steel strip is good,and all the performance indexes meet the requirements of relevant standards and the manufacturing technology of three-phase separator,and the manufacture of the product has been completed.