Abstract: Introduced here in the paper is the R&D of the Φ1 219 mm X80 LSAW Linepipe to be supplied for No.2 West-East Gas Transmission Pipeline Project.The main R & D activities for the said linepipe are mainly concerned with such techniques as JCO forming,welding,mechanical expanding,and auto-ultrasonic detection;results of the physical and chemical property tests and analysis as made to the X80 steel;differences of the tensile properties,the Charpy impact toughness and DWTT of the X80 steel pipe from those of the X80 steel as material;and Charpy impact toughness vs temperature relationship and proper determination of the yield strength ratio of the X80 steel plate,etc.Relevant batch production has proven that all property values of the said pipe has been up to applicable specification,and its material object quality has been up to relevant advanced international level,being the first of its kind in the world.Moreover,thanks to the newly-developed manufacture technology of the said pipe,the cost is tremendously lower than that for producing similar pipes with any other technology.