Normal preterm infants can develop jaundice 2-3 days after birth, with a peak time of 5-7 days and a duration of 3-4 weeks. If breastfed, the jaundice may be delayed to about 4 weeks or even longer. In preterm babies, the jaundice is heavier and lasts longer than in full-term babies because of imperfect liver development and excretory function, and abnormal bilirubin metabolism, and the smaller the gestational week, the longer the jaundice will take to subside, usually lasting 3-4 weeks. Depending on the value of jaundice, blue light irradiation treatment is available, and intravenous application of gammaglobulin is required for hemolytic jaundice. In severe jaundice of prematurity, MRI must be improved to exclude bilirubin encephalopathy. Premature jaundice must be alerted and disposed of promptly. Doctors usually take into account the baby’s gestational age, birth weight, and age at birth to determine whether the indications for phototherapy or blood exchange have been met, in order to prevent aggravation of the condition due to delay.