The invention discloses a preparation method of an O/W type nanometer-level propolis emulsion, and belongs to the technical field of preparation of health-care foods. The method comprises the following steps of: preparing propolis powder; preparing a propolis extractive; preparing a propolis extractive alcohol solution; and making the formula of the O/W type nanometer-level propolis emulsion, preparing the O/W type nanometer-level propolis emulsion, and the like. The preparation method disclosed by the invention adopts the food-level surface active agents; and the product has the characteristics of high edible safety, good water body solubility and physical stability, high oxidation resistance and biological activity, and the like, can be applied to the reprocessing of different-form products, such as oral liquid, a soft capsule, a water-soluble drop or an injection, as a raw material and can be popularized and applied to the related product enterprises.