The invention discloses large lobster feed and a preparation method thereof. The large pobster feed is prepared from a protein source mixture, a carbohydrate mixture, a micronutrient mixture and an adjuvant. The protein source mixture is prepared from fish meal, shrimp powder, silkworm cocoon powder, bean cake, peanut cake and spray-dried animal blood cells. The carbohydrate mixture is prepared from wheat bran, wheat flour, secondary flour, and corn flour. The micronutrient mixture is prepared from clam shell powder, monochoria vaginalis herb, water hyacinth herb, potamogeton wrightii, aegagropila linnaei, coconut slag, palm dregs, soyabean lecithin and seaweed powder. The adjuvant is prepared from multivitamin, choline chloride, mineral element, vitamin C, allicin, cholesterol, taurine, aquatic compound enzyme, prawn shell removing element, 10% olaquindox, L-glycine, sodium humate, gram oxygen, sodium chloride, short chain fatty acids and medium chain fatty acids. The large lobster feed has a comprehensive nutrition, and has good palatability and good feeding property after preparation and processing, and the addition of the short medium chain fatty acids and the compound enzymescan inhibit the growth of pathogenic bacteria.