The development of preterm infants is based on the corrected gestational age. Preterm infants may lag behind normal full-term infants in the development of intelligence, movement and other organs. If the corrected gestational age is not used as the basis for calculation, the true state of development of preterm infants cannot be reflected. In order to accurately assess whether the physical development of a preterm infant is normal after birth, the corrected gestational age is usually calculated by using the original expected date of birth as the date of birth. Through appropriate artificial feeding, supplemental feeding and functional exercises for preterm infants after birth, their body systems, such as respiratory, circulatory, digestive and neurological systems, etc., can develop or even catch up with their development. Generally, preterm infants can reach the level of normal full-term infants by the time they reach 1 year of age after correcting their gestational age.