The most dangerous small bowel necrosis in preterm infants is 2~3 weeks after birth, and in severe cases, it can be delayed to 2 months after birth. Preterm infants should be closely monitored, and symptoms should be treated promptly. The development of the digestive system of preterm infants is not as mature as that of full-term infants, with weak swallowing function, small gastric capacity, poor digestive ability, infection, ischemia and hypoxia of the intestinal mucosa, improper feeding and other factors are all prone to lead to necrotizing small bowel colitis. The high incidence of its disease is 2~3 weeks after birth, and the onset of the disease can be delayed up to 2 months in very low-birth-weight neonates. Treatment includes absolute fasting and gastrointestinal decompression, anti-infective therapy with drugs such as ampicillin, and the need to maintain water-electrolyte balance. Fresh frozen plasma can be delivered in case of coagulation disorders, and surgery can be performed if necessary. The use of specific drugs need to be under the guidance of a doctor, do not take on your own.