It is a difficult subject to develop the high temperature solder with thewhose melting point is within 250～450°C in solder field. Bi5Sb solder alloy whosewith the melting point of about is about 280°C is limited for itshas bad solderability and mechanical properties. In the present work, the new BiSbCu ternary alloy wasis preparformed by adding different contents of Cu to Bi5Sb solder alloy to improve its solderability and mechanical properties. Results showed that the effect of adding 0.5～5.0％Cu into Bi-5Sb on the melting point of Bi5Sb solder alloy wais not distinct , but its solderability and mechanical properties weare markedly improved. Compared to the matrix of Bi5Sb, the spreading area of solder alloy wais about 57.8% largbigger and the tensile strength wais about 212.4% highbigger when the content of Cu wais 1.5wt.%. Analysis of tThe microstructure showeds that the needle-like Cu2Sb gradually becaomes shorter and dense along with the increasing of the content of Cu, which can effectaffected the properties of the solder alloy.