Abstract: 62Sn36Pb2Ag solder and 63Sn37Pb eutectic solder were adopted to join the AgCu alloy bulk and CuBe alloy sheet. The mechanical properties and the relative microstructure for both solder joints were compared and analyzed by the experimental studies. The influence mechanism of Ag element in 62Sn36Pb2Ag on the properties of the AgCu/SnPbAg/CuBe solder joint was elaborated in detail accordingly. The results show that the Ag element in the solder changes the wetting behavior and benefits the less voids, the dispersed distribution of the Ag₃Sn particles contributes the dislocation clinching and results in the higher solder joint strength, and the nearly saturated state of Ag content in the solder joint under the soldering temperature prevents the brittle Ag₃Sn phase enriching near the interface and gives the ideal microstructure of the solder joint.