The invention discloses a nutrition additive of young bird livestock and poultry feed, which comprises: soybean fermentation residue powder, soybean polypeptide powder, cellulase, protease, vitamin D2, D3, vitamin B1, B2, B6, B12, vitamin K, biotin D, vitamin E, mineral powder, and astragalus polysaccharide. The nutrition additive of young bird livestock and poultry feed of the invention can solve symptoms of body low immunity, weak stress resistance, liver dysfunction, digestion dysfunction, infectious disease susceptibility, poor appetite, appetite loss, slow growth, and the like caused by poor nutrient absorption due to poor gastrointestinal digestion absorption functions of young birds, livestock and poultry. When the nutrition additive of young bird livestock and poultry feed of the invention is added into daily ration reasonably, the nutrition additive can promote growth of intestinal villi, improve young animal gastrointestinal functions, improve the feed conversion rate, reduce material consumption, improve immunity and disease-prevention and disease-resistance capabilities of animal bodies, give play to dual effects of nutrition and immunity improvement, and thus improve economic benefits of farmers; the nutrition additive is an indispensable nutritional additive for the development of ecological healthy breeding, and is worthy of popularization.