Abstract: By studying the effect of Cd/Ni element on the microstructures and properties of BAg40 CuZnX solder,the evolution mechanism of high temperature performance of brazed joint was analyzed. The Cd/Ni element has an influence on the melting temperature,wetting fluidity and weld strength of the brazing filler metal. In this paper,the effect of Cd/Ni element on the microstructure and high temperature mechanical properties of brazed joints was studied. Cadmium can improve the comprehensive performance of the brazing filler metal,but at a certain high temperature,the brazed joint structure is quickly embrittled and fractured,which results in the failure of the brazed joint. While nickel can maintain the high temperature mechanical properties of the brazed joint.