The invention discloses a lead-free tin solder with high wettability to a fuse nickel-plated copper cap, high strength and plasticity which comprises 3.0-5.0 percent of Cu, 0.05 --1.5 percent of Sb, 0.05-1.8 percent of Bi, 0.1-0.15 percent of Ag, 0.002-0.25 percent of RE, and the balance Sn by weight. The lead-free tin solder is applicable to the lead-free encapsulation in the electronic industry.