The invention provides infant yak milk formula milk powder and a preparation method thereof. Raw materials for manufacturing products of one ton comprise 100-600 kg of yak milk, 2,000-4,500 kg of fresh milk, 200-500 kg of dried whey (D90), 20-120 kg of whey protein concentrate (WPC34), 0-110 kg of cream, 130-250 kg of refined vegetable oil and OPO structure grease, 15-65 g of lactose, and 0-50 kg of white granulated sugar. The infant yak milk formula milk powder facilitates infant absorption and metabolism, reduces stimulation to a gastrointestinal tract, can remove free radicals, enhances antioxidant ability and immunocompetence of bodies, promotes fat oxygenolysis, promotes human body protein synthesis, and has important function for promoting human body growth and development. The infant yak milk formula milk powder has the important functions for building normal gastrointestinal tract flora, adjusting the balance of various probiotics, stimulating immune cells, promoting intestinal tract movement, and preventing diarrhea and constipation.