Salt　spray　test　on　Al-Li　alloy　1420,　BT20　titanium　alloy　and　their　laser-welded　joints　was　carried　out.　The　test　was　based　on　the　GB/T10125-1997　＇test　standard　for　artificial　atmosphere　salt　corrosion＇.　Polarization　curve　and　neutral　atmosphere　salt　corrosion　test　has　showed　that　the　corrosion　resistant　property　of　BT20　Ti　alloy　is　excellent,　and　mass　loss　of　both　is　not　obvious.　SEM　observation　has　showed　that　the　surface　color　of　1420　Al-Li　alloy　changes　obviously,　and　rust　spot　become　bigger　after　salt　corrosion.