Abstract: In view of the ever-increasing pipeline length and operating pressure, development of high-strength linepipes has become increasingly attractive and needed.The current knowledge of X100 pipeline steel about research and development status, metallurgical principles, mechanical properties, field weldability, and so on were presented.Production of grade X100 steel requires combination of super-clean refining, thermo-mechanical controlled process, proper metallurgical design and some other advanced techniques.Excellent mechanical properties and satisfying weldability are possessed for grade X100 steel.Yield strength of X100 grade steel generally exceeds 690 MPa.High strength-toughness welded joint can be obtained through proper welding procedures.Further work is required to improve the production of X100 pipeline steel and to establish appropriate material standards.