Abstract: Based on the analysis of the chemical composition and mechanical properties, the tensile strength, low temperature impact toughness, hardness, CTOD and HIC of welded joints had been studied on X100 pipeline steel with the selected welding process, welding filler metal and technical parameter. The results show that the welding performance of X100 pipeline steel is good, and the welding process put forward in this paper can meet the working and application requirements.