Abstract: The microstructure,melting behavior,mechanical properties,wettability and interfacial intermetallic compound(IMC) were studied on Sn-Ag-Cu(SAC) lead free solders with different Ag content(0.3,1.0,2.0,3.0,3.8wt%).The result indicates that SAC solders with higher Ag content present finer and denser IMC particles in the bulk solder,as a result of which the tensile strength of SAC solders increases with the increasing of Ag content,while the ductility decreases.The melting temperature of SAC305 and SAC387 solders was close to eutectic point as they have small melting temperature range.It was found that the wettability and interfacial IMC grain size of SAC0307/Cu joint are better than other tested solders.