Abstract: In order to study the properties of welded joints of a new Al-Cu-Li alloy containing Sc,the T6 peak-aged alloy plate was welded by argon-arc welding.The relationships of microstructures and properties of the welded joints were studied by means of tensile test at room temperature,optical microscopy and transmission electron microscopy.The results show that Al-Cu-Li alloy containing Sc can be welded with Al-Cu welding wires containing minor Sc,Zr and Mn using argon-arc welding,the welding coefficient of the weld joint reaches 65%;the tensile samples of welding joint fracture in the head affected zone.The strengthening effect of minor Sc on the weld joint can be interpreted in grain refinement strengthening and precipitation strengthening.