In　this　study,　2195-T8　Al-Li　alloy　joints　were　welded　by　tungsten　inert　gas　(TIG)　welding　with　three　different　gas　protection　strategies.　The　porosity　distribution　of　the　joints　was　quantified　by　Computed　tomography　(CT),　and　the　tensile　properties　of　the　joints　were　evaluated.　The　results　indicate　that　with　appropriate　back　gas　protection,　the　average　ultimate　tensile　strength　and　elongation　of　the　joints　reach　396　MPa　and　5.0　%,　respectively,　increased　by　9.6　%　and　47.1　%　compared　to　the　joints　without　back　gas　protection.　Back　gas　protection　effectively　reduces　porosity　at　the　weld　root,　thereby　preventing　crack　initiation　from　here　during　the　tensile　test.