Abstract: A new welding method named gas pool coupled activating TIG welding was proposed, which contains two layers of shielding gas.The inner inert gas can protect the molten pool, and the outer active gas can provide active element into the molten pool to obtain narrow and deep weld.By taking SUS304 stainless steel as based metal, the effect of GPCA-TIG method on welding arc and weld appearances was studied.In addition, the effect of main welding parameters on weld penetration and D/W ratio was also studied.The results indicate that at the same welding conditions with the traditional TIG welding, the 8 mm thickness stainless steel can be fully penetrated with GPCA-TIG welding process without making a groove.This method can avoid the oxidation of tungsten electrode in welding process.