Transportation　is　a　major　part　of　energy　consumption　and　greenhouse　gas　(GHG)　emissions.　Aluminum　(Al)　as　a　light　metal　can　reduce　vehicle　weight,　energy　consumption,　and　pollutant　emissions,　but　Al　production　is　energy　intensive.　The　main　contents　of　this　study　are　the　following:　(1)　create　the　life　cycle　inventory　of　Al　parts　based　on　the　energy　background　in　China　and　(2)　evaluate　the　energy　savings　and　GHG　reduction　for　the　vehicle　when　steel　parts　are　replaced　by　Al　parts.　Although　there　is　a　considerable　reduction　in　energy　consumption　of　per　tonne　Al　in　China　owing　to　continuing　development　of　process　technology　in　recent　years,　energy　consumption　is　higher　than　the　world　average　level　and　European　level.　Over　the　vehicle＇s　life　cycle　driving　of　200,000kilometers,　the　vehicle　was　found　to　avoid　1,447　to　1,590liters　of　gasoline　consumption　when　six　typical　steel　parts　were　replaced　by　Al　parts.　Based　on　the　current　technology,　the　breakeven　distance　was　calculated,　resulting　in　a　net　energy　benefit　to　use　the　lightweight　Al　parts　compared　with　steel　parts.　A　sensitivity　analysis　was　conducted　to　show　different　energy　savings　by　considering　secondary　weight　reduction　and　different　driving　distance.　The　results　indicate　that　weight　reduction　by　using　Al　is　quite　effective　to　reduce　the　energy　consumption　and　GHG　of　transportation.