In this paper, soldered lap joint specimens were fabricated by a solder reflow process using a Sn-3.8Ag-0.7Cu-xRE (x=0, 0.1wt%, 0.25wt%, 0.5wt%) BGA solder ball on FR4 substrate parts. The effects of rare earth(RE) content and strain rate on the shear properties of soldered lap joint were investigated. The Results show that the addition of minute RE (<0.25wt%) can improve the shear strength and elongation of the lap joint. However, further increasing of RE content would degrade the shear properties of the lap joint. The shear strength and elongation of the lap joint increase with the increase of strain rate. The analysis of the microstructure and fractograph indicated that through the addition of minute RE, the microstructure of the lap joint was refined, especially the growth of intermetallic compound was inhibited, and thus the shear properties of the lap joint were improved. In addition, the observation of fractographs confirmed that the elongation of the lap joint increase with the increase of strain rate