The invention discloses a pig feed and a preparation method thereof. The pig feed is prepared from the following raw materials: corns, wheat, bean pulp, bran, molasses, calcium hydrophosphate, salt, rapeseed dregs, bone meal, fish meal, bitter gourd, sugar beet pulp, loofah sponge, sesame oil, rice vinegar, mushroom freeze-dried powder, yeast powder, garlic powder, agastache rugosus, distillers' grains, lysine, oligosaccharins, bacillus subtilis, enzymic preparations, lactein and gamma-aminobutyric acid. The prepared pig feed can achieve effects of promoting the appetite of big pigs, increasing food intake and improving daily gain, so that the pigs are ruddy in skin and short, sparse and bright in hair, and the meat quality is well improved.