Abstract: 　Objective　To explore the relevant factors that impacted the morbidity and prognosis of early-onset and late-onset necrotizing enterocolitis (NEC) in full-term infants. Methods　A total of 253 full-term infants with NEC hospitalized during 1996 to 2015 were retrospectively analyzed. They were divided into early onset group (onset within one week of birth, n=150) and late onset group (onset after one week of birth, n=103) according to their onset time. The perinatal conditions, co-conditions and complications between two groups were compared. Results　The average gestational age of the early onset group was older than that of late onset group (39.2±1.2 vs. 38.8±1.1), and the morbidity of NEC III stage (27.3% vs.12.6%) and peritonitis (20.7% vs.8.7%) were higher in early onset group than those in late onset group. The differences were statistically significant (P all>0.05). In the early onset group, the proportion of deceased infants with NEC III stage, peritonitis, septicemia, respiratory failure, renal dysfunction, shock, and multi-organ functional disturbance in infants died finally were higher than those survived. In the late onset group, the proportion of infants with NEC III stage, peritonitis, septicemia, respiratory failure, renal dysfunction, and shock in infants died finally were higher than survived infants. The differences were statistically significant (P all>0.05). Logistic regression analysis showed that the risk factors of poor prognosis in early onset group were peritonitis (OR=17.49, 95% CI: 5.89-51.93, P<0.001) and renal dysfunction (OR=10.33, 95% CI: 2.7-154.17, P=0.003), while those in late onset group were peritonitis (OR=20.58, 95% CI: 3.62-116.85, P=0.001) and respiratory failure (OR=12.03, 95% CI: 1.33-109.14, P=0.027). Conclusions　The condition of early-onset NEC was more severe than that in late-onset NEC in full-term infants. In addition, in full-term infants, peritonitis and renal dysfunction were risk factors of poor prognosis in early-onset NEC, and peritonitis and respiratory failure were risk factors of poor prognosis in late-onset NEC.