Premature infants need to drink preterm infant formula because of the imperfect development of various organs, usually corrected to 40 weeks of gestational age, that is, when they reach the normal due date, they can be changed to ordinary formula feeding. Premature infants have not yet developed their gastrointestinal tract functions and have poorer nutritional absorption than full-term infants and higher nutritional needs, so they need to drink preterm infant formula with DHA and ARA, which can promote their brain growth and development and complete catch-up growth in a short period of time. When the child’s weight growth is satisfactory, the feeding, urination and defecation situation is acceptable, and the weight is greater than 5kg, the baby can be gradually replaced with regular formula, and the baby’s growth and development needs to be monitored regularly during the process, and regular medical checkups are conducted. If the baby refuses to eat during the process of changing formula, a small amount of glucose water can be fed, which can play a certain role in the transition. Although preterm formula is nutritious, it still lacks vitamin A and vitamin D. Additional supplementation is needed.