Welding　of　AlSi10Mg　alloys　fabricated　by　additive　manufacturing　(AM)　has　been　recently　conducted　to　meet　the　demands　for　joining　or　repairing　them.　However,　high　susceptibility　to　porosity　occurring　in　weld　metal　(WM)　poses　a　significant　challenge　for　fusion　welding　of　AM　AlSi10Mg　alloys.　The　laser　metal　deposition　(LMD)　process　has　emerged　as　a　promising　welding　solution　due　to　its　low　dilution　rate　for　reducing　the　porosity.　In　this　study,　LMD　welding　of　AM　AlSi10Mg　alloys　was　carried　out　employing　different　heat　inputs　with　five　and　eight　tracks.　The　study　systematically　assessed　the　impact　of　heat　input　on　porosity,　microstructure,　and　mechanical　properties　of　the　welded　joints.　The　results　show　that　the　decrease　of　heat　input　from　180　to　75　J/mm　results　in　a　substantial　reduction　in　porosity　from　7.0　to　2.1%.　This　reduction　leads　to　a　29.4%　increase　in　ultimate　tensile　strength　(UTS)　and　an　11.7%　increase　in　elongation　index　(EI).　Furthermore,　the　upper　region　of　joints　with　eight　tracks　possessing　low　heat　input　displays　lower　porosity　and　superior　mechanical　properties　than　the　bottom　region　with　relatively　high　heat　input.　The　WM　with　eight　tracks　exhibits　refined　alpha-Al　cells　and　Si-rich　eutectic　phases,　improved　connectivity　of　Si-rich　networks,　and　increased　solid　solution　strengthening,　compared　to　the　five-track　joints　with　higher　heat　input.　As　a　result,　low　heat　input　of　the　upper　region　in　the　LMD　welded　joints　has　been　effective　in　minimizing　hydrogen　pores,　enhancing　WM　microstructure,　and　improving　the　mechanical　properties　of　welded　joints　in　AM　AlSi10Mg　alloys.