The　characteristics　of　microstructures,　thermal　properties,　wettabilities　and　mechanical　properties　of　Sn-Bi-In　solders　with　different　composition　were　studied.　The　results　show　that　the　microstructure　of　Sn-Bi-In　solders　consists　of　beta-Sn,　Bi　and　InBi　phases.　The　reduction　of　Bi　content　can　result　in　the　proportion　decrease　of　Bi　and　InBi　phases.　There　are　three　endothermic　peaks　with　different　magnitudes　on　the　DSC　curves,　and　the　onset　melting　temperature　of　solders　are　between　101.3　similar　to　103.4　degrees　C.　With　the　increase　of　Sn　concentration,　the　melting　range　of　solders　firstly　decreases　and　then　increases,　while　the　spreading　area　firstly　increases　and　then　decreases.　The　microhardness　of　solders　increases　with　the　rising　of　Bi　content;　in　addition,　the　hardness　is　remarkably　higher　than　that　of　Sn-Bi　eutectic　alloy　when　the　In　element　is　added　to　solder.　The　tensile　strength　and　elongation　of　solders　decrease　with　increase　of　Bi　content.