Abstract: The coupled arc of twin-electrode TIG(T-TIG)(T:tungsten; I:inert; G:gas)is a kind of particular arc, which is achieved through the coupling of two arcs generated from two insulated electrodes. So it will be different from single arc of common TIG in physical characteristice.Research on T-TIG coupled arc pressure was carried out.Influence of welding current, arc length, the distance between electrode tipe and the shape of electrode on arc pressure were vestigated.