Abstract: S31254 stainless steel, a low carbon and high alloy stainless steel, was used in the Oil Process Project of MIS Oilfield, Iran, which was used rarely in inland. Analysis on its welding performance and field test were made to determine the welding method (pulse argon arc welding) and process parameters. Various defects for S31254 stainless steel from welding course were summarized and treated with relative measures. Necessary investigation procedures made to look through the key quality control measures during welding. Process control of welding quality included groove manufacture, preheating, argon filling protection, temperature control of weld passes, limitations of welding environment and so on. As long as appropriate measures is taken, so it can ensure the welding quality. It is considered that feasible measures and sound process control can effectively eliminate the welding defects with perfect welding quality.