Soft solder alloy used for brazing aluminum and brazing aluminum alloy

The invention discloses soft solder alloy used for brazing aluminum and brazing aluminum alloy. By adding metallic silver and/or copper into metallic tin, low-temperature soft soldering can be realized, and a continuous intermetallic compound layer can be formed on the bonding interface of brazing filler metal, aluminum and aluminum alloy to prevent a galvanic couple from being formed by tin and aluminum, so that the problem that the electrochemical corrosion resistance of welding spots is poor when soft solder containing the metallic tin is used for welding aluminum and aluminum alloy is thoroughly solved.