〔Abstract〕 Objective To study and analyze the risk factors of secondary allergic diseases in children with neonatal necrotizing enterocolitis, and to provide a reference for the prevention and treatment of allergic diseases after neonatal necrotizing enterocolitis. Methods A total of 100 children with neonatal necrotizing enterocolitis admitted to Tianjin United Family Hospital from January 2021 to January 2022 were selected for a 6-month follow-up period, and the occurrence of allergic diseases in the children 6 months after treatment was statistical. According to whether children with neonatal necrotizing enterocolitis had secondary allergic diseases, they were divided into an observation group (allergic diseases) and a control groups (no allergic diseases), and the clinical data of the two groups were compared, and univariate analysis and multivariate logistic regression analysis were carried out for the risk factors of secondary allergic diseases in children with neonatal necrotizing enterocolitis. Results Among the 100 children with necrotizing enterocolitis, 19 children had secondary allergic diseases 6 months after treatment, and the incidence of allergic diseases was 19.00 %. In univariate analysis, there was no significant difference between the observation group and the control group in terms of gender, birth weight, delivery mode, maternal age, etc. (P > 0.05), while the children in the observation group and the control group had significant differences in secondhand smoke exposure history, immediate family allergy history, feeding style, peritonitis, living environment, probiotic application history and other aspects (P < 0.05). Non-breastfeeding, peritonitis, urban life, and non-use of probiotics were risk factors for secondary allergic disease in children with necrotizing enterocolitis (P < 0.05). Conclusion In children with necrotizing enterocolitis, children are prone to secondary allergic diseases due to the influence of secondhand smoke exposure, direct family allergy, non-breastfeeding, peritonitis, urban life, and non-application of probiotics.