The invention discloses fermented soybean meal. Based on 100 parts of soybean meal, a fermenting formula comprises the following raw materials of mixed microbial strains, water, an enzyme preparation and a nutritive aid. The invention further discloses a preparation method of the fermented soybean meal. The fermented soybean meal disclosed by the invention has the beneficial effects that according to the fermented soybean meal produced by the method disclosed by the invention, glycinin in the soybean meal can be degraded to 25mg/g or below, beta-conglycinin is degraded to 15mg/g or below, oligosaccharides are completely degraded, trypsin inhibitory factors are degraded to 0.5% or below, the content of lactic acid is 70mg/g or above, and the quality of the fermented soybean meal is obviously improved; and when the fermented soybean meal produced by the method disclosed by the invention is used for feeding animals, digestion and absorption of feeds are facilitated, the digestion and utilization rate of the feeds is increased, the fermented soybean meal can replace animal-derived protein feed raw materials of fish meal and the like, and can wholly or partially replace organic acids and antibiotics, the raising cost is reduced, and economic benefits are increased.