The low temperature welding technology was studied by the use of the In70Pb30 alloy with 99.9% purity as welding pieces, the influencing factors during welding were analyzed: the influence of welding pieces, heating rate, welding temperature, vacuum degree, the welding pieces were pretreated by the use of formic acid to remove oxide layer, the welding was operated at 215℃, 5×10~(-7) torr under the condition of vacuum, the samples of after welding were characterized by X-ray, pull test system, leakage detect...