In 2016, the Editorial Board of the Chinese Journal of Pediatrics, the Pediatric Health Care Group of the Chinese Medical Association Pediatrics Branch, and the Neonatal Group of the Chinese Medical Association Pediatrics Branch jointly published the Recommendations for Post-discharge Feeding of Preterm, Low Birth Weight Infants [1], which stated that because both fat-soluble and water-soluble vitamins in human milk are difficult to meet the needs of preterm infants to catch up on growth, especially vitamin A (VA) and vitamin D (VD). Therefore, it is recommended that preterm and low birth weight infants should receive VD supplementation of 800-1000 IU/d immediately after birth and 400 IU/d after 3 months of age until 2 years of age. Not only preterm and low birth weight infants have serious vitamin A and D deficiency, but epidemiological surveys in recent years have shown that vitamin A and D deficiency is common among infants and children in China. VA in children under 5 years of age in poor rural areas of six western provinces of China is a severe deficiency [2], and the proportion of vitamin A deficiency (VAD) in hospitalized newborns in a hospital is as high as 96.4% [3], with the lowest serum vitamin A in the 0-1 year old group and the lowest 25-(OH)D in the 7-14 year old group in the resident Beijing urban area, with a detection rate of 43.84% for VAD and 80.17 % for VD deficiency in all examined young children The VAD detection rate was 43.84% and VD deficiency detection rate was 80.17%. Infants and young children are growing rapidly, but their diet is relatively homogeneous and they cannot get as much nutrients from food as adults. In addition, infants and young children have limited stomach capacity and low intake of complementary foods, while carotenoids, which have low absorption and conversion rates, can only be absorbed in the presence of lipids. Therefore, a daily preventive dose of vitamin AD can effectively supplement the missing vitamins A and D in the diet, maintain the normal functioning of physiological functions and promote healthy growth of infants and young children.