C24S Al-Li plates with 2 mm thickness were successfully joined by FSW and TIG welding methods. The microstructure and fracture morphology of welding joints with the two welding methods were observed and analyzed by optical microscopy and scanning electron microscopy,the room temperature tensile properties and micro-hardness were also tested. The results show that TIG welding joint is composed of coarse microstructure,the serious porosity defects and the dissolution of strengthening phases in the weld zone all lead to the decrease of mechanical properties and plasticity,the tensile strength of joint is only 47.9% of the base metal and the microhardness is 92 HV. The welding joint with FSW welding has good formation and small microstructure,the strengthening phase does not dissolve,which leads to the tensile strength of weld joint reach 82.6% of the base metal and micro-hardness is up to 115 HV,and the joint exhibits good plasticity.