The invention belongs to the technical field of thermoelectric materials, and discloses a preparation method of a bismuth telluride thermoelectric material, comprising the following steps: step 1, according to the chemical formula X of N-type bismuth telluride material w / Bi 2 Te 2.7‑ w Se 0.3 Weigh Bi, Te and Se elemental powders as raw materials, or according to the chemical formula X of P-type bismuth telluride material w / Bi 0.5‑w Sb 1.5 Te 3 Weigh Bi, Sb and Te elemental powders as raw materials, X is the doping element, w is the stoichiometric ratio of the doping element X, and the range is 0≤w≤0.1; step 2, mix the above raw materials evenly and place High-energy ball milling is carried out in the ball milling tank of the plasma generator; step 3, the powder in the tank after ball milling is transferred to a sintering mold under an inert gas for sintering, and the sintering is carried out twice, and after cooling, a bismuth telluride thermoelectric material is obtained. The invention combines plasma ball milling and discharge plasma sintering technology to prepare high-performance bismuth telluride material for the first time. The method has the advantages of fast speed, controllable powder composition, low energy consumption and is suitable for mass production.