In　typical　service　environments,　high　current　densities　pass　through　the　interconnection　leads　of　solder　joints.　The　electromigration　reliability　of　solder　joints　is　thus　of　great　significance.　The　microstructure,　crystal　orientation,　and　electromigration　reliability　of　Sn-0.3Ag-0.7Cu-1.6Bi-0.2In　solder　were　studied　in　this　work.　The　results　showed　that　the　melting　point　of　Sn-0.3Ag-0.7Cu-1.6Bi-0.2In　solder　is　212.3　degrees　C,　with　good　wettability.　The　addition　of　Bi　and　In　reduced　the　melting　point　and　undercooling　of　the　solder,　with　improved　solder　wettability.　Compared　with　Sn-3.0Ag-0.5Cu　solder,　the　microstructure　of　the　remelted　solder　was　well　distributed　with　fine　grains.　Compounds　formed　by　substituting　Sn　atoms　with　In　atoms.　Among　the　linear　solder　joints,　those　made　of　Sn-0.3Ag-0.7Cu-1.6Bi-0.2In　showed　easier　formation　of　polycrystalline　structure,　and　the　c-axis　orientation　of　beta-Sn　grains　was　more　disordered.　The　addition　of　Bi　and　In　to　form　Sn-0.3Ag-0.7Cu-1.6Bi-0.2In　affected　the　formation　and　growth　of　intermetallic　compounds　and　improved　the　electromigration　reliability　of　solder　joints.