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, the recommendations emphasize that preterm and low birth weight infants should be supplemented with VD 800-1000 IU/d immediately after birth and 400 IU/d after 3 months of age until 2 years of age, while the recommended VA intake for preterm infants is 1332-3330 IU/(kg・d), which can be supplemented according to the lower limit after discharge from hospital. Not only preterm and low birth weight infants have serious vitamin A and D deficiency, 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 newborns hospitalized in children’s hospitals 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, and the detection rate of VAD in all examined children is 43.84% and the detection rate of VD deficiency is 80.17 percent [4]. Most studies have concluded that retinol is mainly transmitted to the fetus through the placenta during late pregnancy, so the physiological requirements of VA should be supplemented in pregnant women during mid- to late pregnancy and continued in newborns after delivery [5]. Infants and young children grow rapidly, but their diet is relatively homogeneous and they do not 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 lack of vitamins A and D in the diet, maintain the normal functioning of physiological functions and promote healthy growth of infants and young children.