The investigation status of Sn-Ag lead-free solders Is reviewed comprehensively. The effects of Bi
In
Zn
Al
Cu
Ni
Sb et al rare earths and nanoparticles on the wetting properties
melting temperature
mechanical properties
microstructure and interfacial reactions are discussed. In addition
the problems in the study of Sn-Ag solders are discussed and solutions are proposed. It provides a reference for the research of Sn-Ag lead-free solder.