Currently,　three-dimensional　packaging　(3D　packaging)　is　used　as　the　most　feasible　technological　way　to　break　Moore＇s　law.　In　3D　packaging,　three　different　sizes　of　solder　joints　must　work　together　to　achieve　highly　integrated　vertical　interconnects.　This　architecture　needs　to　be　realized　by　multiple　reflow　in　industrial　production.　Therefore,　it　is　necessary　to　choose　three　solders　with　different　melting　points.　In　order　to　further　extend　the　reflow　temperature　range　and　increase　the　flexibility　of　3D　integration,　the　development　of　low　melting　point　solders　is　required.SnBi　solder　joints　often　suffer　from　brittle　fracture　due　to　the　inherent　brittleness　of　Bi,　and　SnIn　solder　joints　is　limited　in　its　low　tensile　strength.　Therefore,　a　series　of　SnBiIn　alloys　with　different　ratios　were　prepared.　During　the　composition　design,　orthogonal　experimental　method　was　used　to　determine　composition　ratios.　The　effects　of　different　composition　on　the　micro-morphology　as　well　as　the　mechanical　properties　of　SnBiIn　alloys　were　investigated.　Samples　were　prepared　using　a　vacuum　induction　furnace　and　the　microstructure　of　the　samples　was　analyzed.　The　mechanical　properties　of　the　alloys　with　different　compositions　were　measured　by　tensile　test.　The　results　of　this　study　provide　a　research　basis　for　the　design　of　low　melting　point　solder.