The invention relates to an additive for 
smelting aluminium alloy and a preparation method and an application method thereof, relating to the technical field of nonferrous 
alloy manufacturing with a special additive. The additive is composed of 
metal powder, cosolvent, heat-generating agent, detonating agent and 
moisture proof agent. The preparation method comprises the following steps: raw materials comprising the following by 
mass percentage, 70-81.5% of 
metal powder, 15-20% of cosolvent, 2-5% of heat-generating agent, 1-3% of detonating agent and 0.5-2% of 
moisture proof agent, are fully mixed evenly into compound 
powder with a 
ball mill, and the mixture is put into a mould, and is performed with cold pressing by a 
hydraulic pressure machine so as to obtain the additive for 
smelting aluminium alloy. The application method of the invention comprises the following steps: a 
graphite crucible filled with a pure 
aluminium pig is arranged in a resistance furnace to be heated until the aluminium pig is melted into aluminium liquid, and then the additive is added to react with the aluminium liquid so as to obtain 
aluminium alloy. Under the condition that the quality of 
aluminium alloy is not lowered, the additive solves the problems of high dissolving temperature, low absorptivity and unstable absorptivity of the additive.