Sn-Bi-In　low-temperature　solder　was　fabricated　by　adding　In　element　to　tin-bismuth　series　solder.　In　this　paper,　to　study　the　solders　with　melting　temperature　around　110　degrees　C　for　replacing　the　toxic　26Sn-54Bi-20Cd　alloy,　the　microstructures,　thermal　properties,　wettabilities　and　microhardness　of　solders　were　studied　respectively.　The　results　show　that　the　microstructure　of　Sn-Bi-In　solders　is　composed　of　BiIn2　matrix,　InSn4　and　Bi　phases,　and　transformed　to　Sn-rich　matrix,　Bi　and　InBi　phases　with　the　In　content　reduction.　In　addition,　the　melting　temperatures　of　solders　with　12wt%　In　content　are　around　101.5-103.1　degrees　C.　Wettability　is　affected　by　compositions　and　the　increase　of　Sn　content　to　50wt%　can　promote　the　spreading　of　solders.　Microhardness　can　be　increased　by　Bi　addition　and　In　reduction.　Based　on　these　properties　study,　50Sn-38Bi-12In　solder　is　comparable　to　26Sn-54Bi-20Cd　solder,　and　could　be　used　in　the　special　low-temperature　welding.