Bi-based solders have low price, low melting point, good wettability and fatigue resistance. Many Bi-based solders can form stable eutectic structure at low temperature, and the addition of a few elements such as Ag, Cu, Co and other elements can significantly improve their physical and chemical properties. Bi-based non-lead solder provides another stable welding temperature choice for the continuous development of miniaturization, high density, multi-function and thinness of electronic products, especially civilian consumer electronic products.