The invention provides a manufacturing method for a pre-alloying gold-tin pre-forming soldering lug. The process of the method mainly comprises five steps such as raw material preparation, pre-alloying, hot rolling, annealing and blanking forming. Due to the fact that N2+H2 mixed protective gas is injected into a vacuum melting protective system to conduct the pre-alloying, gold-tin alloy is not prone to be oxidized in melting process. Due to adoption of the hot rolling and annealing blanking of gold-tin materials after the pre-alloying, a machined gold-tin soldering lug is accurate in composition, complete and precise in shape and excellent in soldering using performance. Meanwhile, the manufacturing method for the pre-alloying gold-tin pre-forming soldering lug has the advantages of being simple in technology and process, reasonable in production cost and high in production efficiency.