The invention relates to a Yunnan black tea essential oil and a preparation method thereof. The essential oil is prepared by a supercutical fluid extraction-molecular distillation combination technique. The preparation method comprises the following steps: carrying out supercritical extraction on Yunnan black tea, and carrying out molecular distillation to obtain the Yunnan black tea extract. Compared with the traditional extraction method, the invention adopts the newest supercutical fluid extraction-molecular distillation combination technique, has the advantage of high extraction efficiency, does not introduce any harmful organic reagent, and obtains the Yunnan black tea essential oil with no solvent residue and with good scent and quality under the conditions of low temperature and low pressure. The method is simple to operate, has the advantages of high extraction rate and no pollution, and provides an efficient green environment-friendly extraction separation method for preparing Yunnan black tea essential oil.