The invention discloses a full-position connecting pipe and safety end circular seam welding method achieved through tungsten electrode inert gas arc welding. According to the method, nickel base alloy serves as an isolating layer to carry out machining on a connecting pipe and a safety end so that a welding groove can be formed by the connecting pipe and the safety end during assembling, and the welding groove is welded. A plurality of weld beads are welded during welding, the bottom end of a part to be welded is arced during welding, spin welding is carried out along one side of the part to be welded to the top end of the part to be welded, arcing is stopped, the bottom end of the part to be welded is arced again, spin welding is carried out along the other side of the part to be welded to the top end of the part to be welded, and arcing is stopped. When the welding groove is a double-faced U-shaped narrow gap groove, an outer groove is welded but not completely welded, back chipping and complete welding are carried out on an inner groove, and then complete welding is carried out on the outer groove. When the welding groove is a single-faced narrow gap groove, the groove is completely welded, a cushion plate is removed, and back chipping is carried out.