MAB phase is a ternary transition metal boride, and MoAlBMoAlB is one of the typical compounds of MAB phase. It has become a research hot spot because of its excellent electrical-thermal conductivity, high hardness, fracture toughness, and corrosion resistance. To prepare MoAlBMoAlB with low cost and green process, an innovative idea was proposed by using Mo, Al2O3 and B2O3 as raw materials by molten salt electrochemicalMolten salt electrochemical method. The theoretical feasibility of this mixing for MoAlBMoAlB was analyzed by thermodynamics, and provided thermodynamic calculation of free energies to produce MoAlBMoAlB phase. The results showed that to obtain MoAlBMoAlB the molar ratio of Mo, Al2O3 and B2O3 was 1:0.6:0.5 and raw materials could not react with NaCl–CaCl2 at lower than 1200 ℃. B2O3 was easier to electrolysis than Al2O3, B and Al were obtained by electrolysis at 700–1000 ℃ when the decomposition voltage was −2.64 to −3.12 V. Mo and B formed MoB alloy which then reacted with Al to form MoAlBMoAlB. Under the above thermodynamic conditions, the preparation of MoAlBMoAlB by molten salt electrochemicalMolten salt electrochemical method was predicted.