In this paper, the process of Cu-Ag contact wire with adding rare-earth elements was presented. The additive process of the rare-earth elements and the function of the rare earth were chiefly analyzed. Adding the rare-earth elements into melt alloy, the oxide and sulfur can be removed from the liquid, so we can get the purified alloy. At the same time, adding rare-earth can reduce the external crack flaws which produced during the casting and makes the grain refined, as the result, the properties of the Cu-Ag alloy contact wire can be greatly improved and meliorated. Such as the conductivity, the specific elongation, tensile strength and so on, are improved.