Under normal circumstances, full-term newborns can start vitamin D supplementation at half a month, while premature babies are more prone to vitamin D deficiency and it is recommended to start supplementation around 1 day after birth. Whether breastfed or artificially fed, newborns need to be given 400 units of vitamin D supplementation daily after 1-2 weeks of life, and long-term supplementation is recommended. Vitamin D supplementation for newborns can enhance calcium absorption, prevent pediatric rickets, osteomalacia, corpus cavernosum and funnel chest, improve sleep quality, promote infant bone development, and prevent developmental delays. In addition to oral medication for vitamin D, parents also need to expose their infants to sunlight to help convert the vitamin D taken from food into active vitamin D. In addition, vitamin D is available in capsule or liquid form. Parents can open the capsule and squeeze the vitamin D directly into the infant’s mouth, while the liquid form can be dripped directly into the mouth. However, if the baby does not cooperate, it can be put in the milk for feeding together.