Abstract: Introduced in this paper is the research and development of X70QS seamless steel pipe for linepipe for sour service.Briefed are the chemical composition and the manufacturing process flow of X70QS seamless steel pipe for linepipe.Analyzed are the tensile strength, the impact toughness, the hardness, the metallographic structure and the corrosion resistance of the produced Φ168.3 mm×18.26 mm X70QS seamless steel pipe for linepipe.The analysis shows that all the mechanical properties of the X70QS seamless steel pipe for linepipe can satisfy the requirements of relevant standards and the needs of users.