Abstract: In this paper a novel high temperature Pb-free solder is formed by adding 1%~8% Sn into the matrix of Bi5Sb.Influences of different contents on solderability and mechanical properties of Bi5SbxSn alloy have been studied.The results show that compared to Bi5Sb solder,effect of adding appropriate Sn into Bi5Sb solder on the melting point of Bi5SbxSn solder alloy is not distinct,which is about 270~280℃,but its spreading properties and tensile properties are markedly improved.When the content of Sn is 8%,its spreading properties and tensile properties are best,and its spreading area and tensile strength are 22 mm² and 40.4 MPa.Compared to the matrix of Bi5Sb,the spreading area and tensile strength of the Bi5Sb8Sn solder alloy are improved by one times and three times respectively,analysis of the microstructure shows that it is closely related to new phases β-SnSb dispersed in the Bi5Sb8Sn solder alloy.