The characteristics of microstructures, thermal properties, wettabilities and mechanical properties of Sn-Bi-In solders with different content were studied. The results show that the microstructure of Sn-Bi-In solders consists of β-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 around 101.3-103.4℃, 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 mircrohardness of solders increases with the rising of Bi conetent, in addition, the hardness is remarkably higher than Sn-Bi eutectic alloy when the In element is added to solder. The tensile strength and elongation of solders decrease with reduction of Bi content.