Third generation Al-Li alloy 2195 and 2198 were studied. The material properties of these two Al-Li alloy were compared with traditional alloy 2024; damage tolerance properties was tested and compared with 2024 as well. Microstructure of parent material and welded sample was studied and compared. Crack growth rate was tested and compared. Some conclusions were drawn: Al-Li alloy had a great strength and damage tolerance; local inhomogeneities microstructure in welded samples, which created the difference of damage tolerance and the tendency of crack growth rate in welded samples.