Abstract: Starting from the principle of the pre-welding/finish welding technology for the oil/gas transmission pipe,the co-authors present here in the paper a detailed description of the series breakthrough in the aspects of the typical key techniques of the pre-welding/finish welding processes(i.e.,the hi-efficiency pre-welding technique and the quality multiarc finish welding technique),and digitalized pre-welding/finish-welding equipment.Moreover the actual application status of relevant techniques and equipment in some representative projects are elaborated.Compared with the conventional so called“One-step Method”welding process,the said pre-welding/finish welding process and equipment are capable of producing the pipe featuring high impact toughness of the weld seam,small dispersion,and nice-shaped,bright and clean,and smooth weld seam.Moreover the primary weld seam qualification rate,the yield and the production capacity are all enhanced.And the electrical energy is saved by approximately 17%.