The　influence　of　natural　aging　on　joint　microstructure　and　mechanical　properties　of　fiber　laser-variable　polarity　TIG　hybrid　welding　of　4　mm　thick　A7N01　Aluminum　Alloy　was　investigation　by　OM,　DSC,　TEM　analysis　and　mechanical　properties　test.　The　experiment　results　show　that　the　joint　mechanical　properties　was　significantly　improved　and　achieved　stability　after　natural　aging　of　30　days,　and　the　joint　average　tensile　strength　was　369　MPa,　which　is　equivalent　to　83%　of　base　metal.　The　tensile　strength　was　increased　by　about　15%　more　than　that　of　as-welded　joint　and　the　elongation　was　increased　from　3.1%　to　4.4%.　For　the　joint　of　natural　aging　of　60　days,　the　tensile　strength　was　increased　to　394　MPa　by　removed　the　reinforcement,　achieve　the　94%　of　that　of　base　metal,　and　the　elongation　was　achieved　to　7.6%.　The　tensile　fracture　occurred　in　the　fusion　zone,　and　the　fracture　morphology　was　distinctly　ductile　characteristics.　After　natural　aging,　the　joint　microstructure　did　not　significantly　change,　but　the　number　and　the　size　of　precipitated　phase　was　increased.　The　precipitation　were　mainly　GP　zone　and　little　of　η＇　or　η　phase.　The　precipitated　phase　can　improve　the　strength　of　welded　joint　by　pinning　dislocations.　©　2018,　Editorial　Board　of　Transactions　of　the　China　Welding　Institution,　Magazine　Agency　Welding.　All　right　reserved.