JLSP optimized welding technology and welding materials and improved toughness index of welding joint superior to standard requirements through researching and developing the new achievement. JLSP optimized the composition of steel plate and rolling technology cooperated with steel mills. The forming technology of X80 steel pipe with large diameter and heavy wall is innovated and the problem of dimension control precision of high grade and heavy wall steel pipe is solved. Innovated residual stress control technology, residual stresses of steel pipe are reduced significantly.