Preparation method of pig feed

The invention relates to a preparation method of pig feed. The preparation method of the pig feed comprises the following steps: mixing low wine and vinegar according to the volume ratio of 3:1 to 5:1to obtain a mixed solution, wherein the alcoholic strength of the low wine is 30 to 40 degrees; adding 15 to 25 parts of bean pulp into the mixed solution, leaving to stand for 4 hours and filtering;heating the bean pulp to 85 to 90 DEG C, and mixing and stirring the bean pulp, 12 to 18 parts of mushroom bran with white mycelium, 4 to 6 parts of water and 0.1 to 0.2 part of combined bactericideuniformly; standing on the ground, performing anaerobic fermentation for 6 to 8 days, turning over for one time, adding 6 to 8 parts of water and performing anaerobic fermentation for 5 to 7 days again; sealing for 3 to 4 days and mixing 65 to 75 parts of corn, 10 to 15 parts of bone meal, 5 to 10 parts of fish meal and 3 to 5 parts of stone powder. By the preparation method, anti-nutritional factors in the bean pulp can be