The invention relates to a preparation method of hydrofluoroether. The preparation method comprises the following steps: (1), dissolving an alkali compound in fluorine-containing alkanol, adding a solvent, adding fluorinated olefin, and heating and stirring for reaction to obtain a mixed solution; (2), washing the mixed solution obtained in the step (1) by using water, standing for demixing, collecting an organic phase solution of a lower layer, and rectifying to obtain a hydrofluoroether product. According to the preparation method, the generation of double-bond impurities can be inhibited, and a reaction product from which a target product is easily purified can be obtained; the reaction temperature and the reaction pressure are relatively mild, the safety coefficient is high, and more satisfactory reaction speed can be obtained; the solvent is easily recycled, the cost is lowered, and a plurality of wastes are prevented from polluting the environment.