With the development of perinatal and neonatal medicine, more and more preterm infants of small gestational age and low birth weight are surviving, but in recent years, the phenomenon of extrauterine growth retardation (EUGR) in preterm infants has attracted widespread attention, and the nutritional status of many preterm infants is off target. Proper nutritional support is not only related to immediate growth and disease regression, but also has a direct impact on long-term prognosis. Adequate and balanced nutrition is the material basis for healthy growth of preterm infants. After completing the first to second stages of the nutritional management program for preterm infants during hospitalization, babies automatically enter the third stage after discharge – the “post-discharge period”, i.e., management from discharge to 1 year of age. Scientific nutritional management facilitates the physical growth of preterm infants, promotes neurological development, and reduces the risk of chronic diseases associated with adulthood. The purpose of post-discharge nutritional management is to help preterm infants achieve ideal nutritional status and meet their needs for both normal growth and catch-up growth. The focus includes feeding and assessment of growth and metabolism. The frequency of monitoring is once a month after discharge up to 6 months of age, once every 2 months from 6 to 12 months of age, and once a month for high-risk preterm infants. Monitoring items 1. Feeding assessment The first assessment should be performed within 1-2 weeks after discharge, including the type of milk fed, the daily milk quantity, the time required for each feeding, the presence of choking, vomiting, the number of stools and bowel movements, and other characteristics. The basic indicators include weight, length and head circumference. At present, different methods are used to evaluate the physical growth of preterm infants according to the gestational age before 40 weeks and after 40 weeks. Before 40 weeks of gestational age, refer to the growth curve of preterm infants (see the figure below), and after 40 weeks of gestational age, according to the corrected age, refer to the growth standard of normal infants in China (see the figure below). Since the catch-up growth of preterm infants is often shown within one year of age, especially in the first six months, the ideal level of weight gain within 6 months of corrected gestational age should reach the 25th to 50th percentile of the standard for the same gestational age, followed by length growth, while head circumference growth is especially important for the development of the nervous system. 3. Nutritional metabolic assessment The nutritional status of preterm infants should not be limited to growth monitoring, especially for high-risk infants, but should be combined with the comprehensive assessment of blood nutritional metabolic indicators. Commonly used indicators include hemoglobin, urea nitrogen, alkaline phosphatase, calcium, phosphorus, prealbumin and 25 hydroxyvitamin D, etc. Generally speaking, the duration of fortification for high-risk preterm infants should be about 6 months, but if the growth target can be achieved earlier, fortification should be gradually stopped to avoid overfeeding. Premature infants with more complications and intra- and extra-uterine growth retardation may need to be fortified until the corrected age of 6 months or older, or even 1 year. Depending on whether the physical growth indicators reach the 25th to 50th percentile at the corrected month of age, or the 10th percentile for children younger than gestational age, and whether the rate of weight gain is satisfactory, gradually discontinue feeding fortification after the catch-up goal is reached. Care was taken to avoid weight greater than the 90th percentile. The institutionalization and standardization of medical management of preterm infants after discharge from the hospital requires not only the growth of the professional team of child health care, but also the understanding and cooperation of the guardians, and the dissemination of medical science knowledge is also essential.