The invention relates to a preparation method for titanium-aluminium alloy, belongs to the field of alloys and aims to solve the technical problem of providing the preparation method for the titanium-aluminium alloy. The preparation method comprises the following steps: titanium serves as an anode and liquid aluminium serves as a cathode and then titanium and liquid aluminium are electrolyzed in a fused salt electrolyte to prepare the titanium-aluminium alloy, wherein the fused salt electrolyte comprises the main body fused salt NaCl-KCl and soluble titanium salt; the mass ratio of the NaCl-KCl to the soluble titanium salt in the fused salt electrolyte is 100 to 1-10; the weight of the soluble titanium salt is measured by the weight of titanium. According to the preparation method for the titanium-aluminium alloy, as liquid aluminium is adopted to serve as the cathode and is alloyed in a smelting state, the alloyed titanium aluminium alloy sinks at the bottom of a crucible and is easy to separate; the obtained titanium-aluminium alloy products are spongy and easy to wash, the impurity content is less and the follow-up processing is facilitated.