Abstract: Effect of Sb on the wettability of Sn-0.3Ag-0.7Cu lead-free solders was investigated, with different atmospheres and fluxes, the wetting balance tester was used to analyze the wettability of Sn-0.3Ag-0.7Cu-xSb solders. The results indicates that small amount of Sb can enhance the wettability of Sn-0.3Ag-0.7Cu solders. With the N₂ atmosphere, the wettability of Sn-0.3Ag-0.7Cu-xSb can be increased obviously, which can be attributed to the resistance of oxidation (molten solder). Combing different fluxes, the wettability of lead-free solder can represent variation, the suitable flux can improve the wettability of Sn-0.3Ag-0.7Cu-xSb solders.