With　the　diversification　of　manufacture　methods,　joining　the　same　materials　with　different　states　becomes　indispensable　in　practical　application.　In　present　work,　6061　aluminum　alloys　with　different　states　were　welded　by　laser　beam　welding　(LBW).　The　microstructures　of　welded　joint,　before　and　after　heat　treating,　were　investigated.　The　mechanical　properties,　such　as　the　tensile　properties　and　microhardness,　were　tested.　And　the　fracture　characteristic　was　observed　by　means　of　scanning　electron　microscope　(SEM).　The　results　show　that　the　6061　aluminum　alloys　have　superior　weldability　and　the　microstructures　are　different　significantly　in　different　states.　Besides,　the　grain　boundaries　of　the　joint　microstructures　become　unclear　after　the　heat　treating.　The　strength　and　the　elongations　of　welded　joints　could　reach　to　those　of　the　base　metal.　The　tensile　fracture　occurs　in　the　fusion　zone　and　near　6061-O　alloy.　And　the　fracture　presents　ductile　rupture.　Therefore,　the　LBW　is　an　effective　method　for　6061　aluminum　alloy.　©　2011　Editorial　Board　of　CHINA　WELDING.