Thermal fatigue is a major source of failure of solder joints in surface mount electronic components. Through analyzing and summarizing the leadfree solder joint thermal reliability at home and abroad, this paper emphatically expounds the influence of the solder Ag content, thermal cycle parameters and solder joint microstructure on the thermal reliability of leadfree solder joints. Finally, the paper analyzes the challenges and the developing trend of the leadfree solder joint thermal reliability. The hotspot and challenges in the future research by microstructure analysis and modeling, the influence of thermal load analysis and the construction of physical failure model of solder joint, etc. are going to be researched further.