Abstract: The method of the Deep Penetration Tungsten Inert Gas Welding is obtain the arc with the characteristic of high energy density and high arc degree based on the efficient cooling of tungsten , compression of arc, and to realize the types of perforation welding, with deep penetration. Base materials of low carbon steel and stainless steel were used, the stable keyhole welding was achieved by adjusting the process parameters, which can realize one-side butt welding with back formation without grove for the low carbon steel plate with the thickness thinner than 10 mm and stainless steel plate with the thickness thinner than 12 mm, respectively, and the TIG welding efficiency was greatly improved.