The invention provides a preparation method of a vanadium-aluminium alloy. The method comprises the steps as follows: (1) after raw materials including vanadium oxide, a carbonaceous reducing agent and metal aluminium are evenly mixed, a binder and water are added, and a pellet is produced through even mixing and pelleting; (2) the produced pellet is placed in a vacuum furnace for a reduction reaction at 1,250-1,800 DEG C, a reaction product is subjected to subsequent treatment, and the vanadium-aluminium alloy product is obtained. With the method, raw material components and the ratio are adjusted, the vacuum reduction method is adopted, the technological process is optimized, no auxiliary materials such as a heat elimination agent, fluorite and the like are required to be added in the whole process, the requirements for the raw materials are relatively low, the technology is simple, the recovery rate of vanadium is greatly increased, and the prepared vanadium-aluminium alloy has the low impurity content.