The invention discloses a slow-release injection emulsion for treating bovine copper deficiency, which is characterized in that it is mainly made of the following raw materials by weight: organic copper powder 5-10, glycerin 18-37, liquid paraffin 43 -86, Tween 802-5, Span 805-10, co-emulsifier 1-3. And by first preparing the water phase and the oil phase, and then preparing the required injection emulsion in one step. The injection obtained in the present invention is an emulsion, and the copper is coated by high-speed stirring to obtain a uniform water-in-oil system, which prolongs the action time of the drug and has a slow-release effect; the copper is coated to increase the surface area of the drug , the chance of drug molecule crystallization is reduced, and the stability of the drug is increased; at the same time, the present invention has simple production process, accurate dosage, easy operation, and can complete the production of the emulsion in one step.