The invention discloses low-temperature lead-free solder and used for 
welding electrical contact materials. The low-temperature lead-free solder comprises, by 
mass percent, 30%-65% of Bi, 15%-50% of Sn and 15%-45% of In. To improve the mechanical performance of the 
alloy solder and improve the 
oxidation resistance, the wettability and the like, one or more of microelements including Ag, Zn, Al, Cu, Ga, P and the like is appropriately added. The 
melting point of the low-temperature solder is controlled within the range of 75 DEG C-100 DEG C, is used for removing damage of 
welding temperature toa welded object in the 
welding process and has the advantages that the 
melting temperature is low, during welding, the binding rate with 
copper foil is high, the loss tangent value of a 
capacitor issmall, the partial discharging performance and the 
overvoltage and large current resistance of the 
capacitor are improved, the cost is relatively low, no lead exists and the low-temperature lead-freesolder is more 
environmentally friendly. The low-temperature lead-free solder is especially suitable for welding 
heat sensitive elements, 
semiconductor elements with 
semiconductor manner refrigeratingelements and the like.