The invention discloses a health feed additive for livestock and poultry. The additive is prepared from combination of the following raw materials by weight: 10-50g of oligosaccharides in every kilogram of the additive, 1000-10000 billions of bacillus, and the balance of edible mushroom residue albumen powder, wherein the oligosaccharides are 2-10 monosaccharides, namely malto-oligosaccharide, galactooligosaccharide, manno-oligosaccharide, soybean oligosaccharide, xylooligosaccharide, fructo-oligosaccharide, chitosan oligosaccharide and seaweed oligosaccharide in a ratio of (0-1):(2-4):(1-2):(0-1):(0-1):(0-1):(0-1):(0-2). The edible mushroom residue albumen powder is mixed mushroom residue of one or two or more of edible mushrooms after 2-3 crops of cultured mushrooms, and is prepared by drying, grinding, soaking, boiling, carrying out enzymolysis, filtering to obtain filtrate, concentrating the filtrate and drying. The additive can be used for improving the digestion and absorption rate of gastrointestinal tracts, promoting the metabolism of livestock and poultry, improving the disease resistance of bodies, promoting animal growth and improving the breeding benefit.