The invention discloses a method for producing a compound microbial preparation serving as fodder, which comprises the steps of microbial inoculum production, material proportioning, bacillus subtilis medium preparation, beer yeast medium preparation and lactobacillus plantarum medium preparation. According to the method, bacillus subtilis, beer yeast and lactobacillus plantarum are bred to form compound strains, so that the totality of the compound thalli is increased, and the advantages such as high strain survival rate, strong stability and the like are achieved; the compound thalli are mixed with ball-milling chaff, bran and oligoisomaltose in a proper proportion, and the optimum compounding proportion is formed for the preparation; good conditions are created for the formation of the internal environment of intestinal canals of livestock and poultry, the aerobic bacillus subtilis interacts with yeast to generate more nutrient substances, amylase, protease cellulose and the like; and meanwhile, oxygen in the intestinal canals of livestock and poultry can be consumed, excellent growth environment is created for propagation of lactic acid bacteria, intestinal canal functions of livestock and poultry are improved, the fodder conversion rate is improved, and the microecological balance of the intestinal canals of livestock and poultry is improved.