The invention provides an aluminium alloy for a vehicle hub and a preparation method thereof. The alloy comprises the following components by weight percent: 4.5-6.3% of Zn, 1.4-2.5% of Mg, 0.5-0.9% of Cu, 0.12-0.3% of Zr, 0.05-0.15% of Ti, 0.05-0.2% of Cr, 0.1-0.3% of Sc and the balance of Al. The preparation method of the aluminium alloy comprises the following steps: weighting raw materials, melting the raw materials except for magnesium blocks, adding a covering agent, then adding the preheated magnesium blocks, stirring, injecting nitrogen or argon to degas, filtering with a ported ceramic plate, reducing the temperature, standing for 20 minutes, and adopting a liquid forging mould and a liquid forging forming method to prepare the hub. The prepared vehicle hub has high strength, impact toughness and corrosion resistance; and the mechanical properties of the aluminium alloy hub can be ensured, the production cost can be reduced and the large-scale production of the hub is easy to perform.