In　this　study,　an　analytical　model　was　established　for　calculating　solute　distribution　pattern　and　precipitates　of　the　Al-Mg-Si　series　alloys　resistance　spot　welds.　By　coupling　the　model　with　a　thermodynamic　database,　a　volume　element　Omega　was　considered,　then　used　to　calculate　the　effective　Mg　and　Si　concentration　in　alpha-Al　solid　solution　under　different　post-weld　heat　treatment.　Resistance　spot　welding　test　of　Aluminum　alloys　6061　and　6082　was　carried　out,　followed　by　sample　characterization　via　transmission　electron　microscopy　(TEM).　Analysis　of　beta-Mg2Si　phase＇s　distribution　revealed　that　Mg　and　Si　were　segregated　at　the　inter-granular　region　after　welding.　Notably,　the　beta-Mg2Si　phase　was　dissolved　during　post-welding　solid　solution　treatment,　thereby　making　Mg　and　Si　to　diffuse　into　the　inner　granular　region.　This　solute　redistribution　process　was　consistent　with　C-f(S)　curves　evolution　calculated　by　the　analytical　model.　The　calculated　effective　Mg　and　Si　concentration　set　up　a　platform　for　further　calculation　of　precipitate　evolution　curves.　Precipitate　mole　fraction　was　positively　correlated　with　the　weld＇s　strength.　(c)　2021　The　Author(s).　Published　by　Elsevier　B.V.　This　is　an　open　access　article　under　the　CC　BY-NC-ND　license　(http://creativecommons.org/licenses/by-nc-nd/4.0/).