Adding microelements Ag In Ga and Sb into Sn-20Bi solder, the changes of melting properties and microstructures of the solder were observed. The experimental result showed that when the content of Ag was 0.7% (wt%), In was 0.1% , Ga was 0.5% and Sb was 0.5%, the melting points of the solder reduced to the bottom and the segregation of Bi obviously decreased. Sb was not suitable to add solely but when it was added together with Ag In and Ga, it can produce a good effect on reinforcement of solid solution, furthermore it can restrain the phase change of Sn. The Sn-Bi-X solder with the best compositions of Ag In Ga and Sb has a near melting point to Sn-37Pb. The solder is close to practicality without segregation of Bi.