Premature babies advocate breastfeeding, no breast milk before choosing preterm formula feeding, and how long to eat preterm formula can not simply depend on the child’s weight. Breast milk contains more protein, essential fatty acids, energy, minerals, trace elements and immune components such as secretory IgA and lactoferrin, which can enable preterm infants to recover to their birth weight in a short period of time and enhance their immunity. When breast milk is sufficient, breastfeeding is advocated for both full-term and preterm infants. When breast milk is not available, preterm infants fed with preterm formula should preferably be changed according to the growth curve and under the guidance of a professional doctor. Generally, the organs of preterm infants are less developed, more functional, less able to live and less resistant, so feeding preterm infants is especially important.