The invention relates to oil, especially to an emulsified oil which is suitable for being added into livestock feed and a preparation method thereof. The emulsified oil comprises the following components of: by weight, 40-100 parts of vegetable oil, 0.5-5 parts of span, 1-10 parts of monoglyceride stearate, 1-5 parts of sodium caseinate, 1-10 parts of disodium hydrogen phosphate and 30-90 parts of glucose syrup. The emulsified oil is prepared by technological processes of burdening, homogenization, spray drying and cooling. The emulsified oil provided by the invention has balanced nutrient proportion, is rich in medium / short chain aliphatic acid, high nutritional milk protein, digestible monosaccharide and the like which are all easy for animals to absorb, has high net energy value and high digestion and absorption rate, can greatly increase the content of fat in feed and raise energy density of animal diets, is a powered solid, and is convenient to preserve and transport.