Preparation method of fermented feed

The invention relates to a preparation method of a feed, in particular to a preparation method of a fermented feed, which comprises the following steps: taking 500 parts by weight of bean dregs as a solid fermentation culture medium, then taking bacillus subtilis and candida utilis to ferment for 12 hours, and filtering to obtain the fermented feed. 14-16 parts of lactobacillus plantarum, MgSO4. 7H2O and a carbon source are mixed and added into a solid fermentation culture medium to form a culture medium; finally, the culture medium is placed in a fermentation bag to be subjected to sealed anaerobic fermentation for 5-7 days, and the fermentation temperature is kept at 36 DEG C; various complex enzyme systems generated by bacillus subtilis, candida utilis and lactobacillus plantarum are used for degrading various anti-nutrient substances, the removal rate of phytic acid and trypsin inhibiting factors in the bean dregs is increased, meanwhile, lipoxygenase in the bean dregs is completely removed, and the nutri