Objective To evaluate the value of monitoring circular blood interleukin(IL)-17 for predicting 60 d mortality rate in premature infants with necrotizing enterocolitis(NEC).Methods A total of 85 neonates with surgically or medically treated NEC were retrospectively included.Serum IL-17 level was detected in diagnosing NEC and before preparing operation for evaluating its predictive value.Results The mortality rate after 60 d was 20 ％ (17/85),in which 5 (10 ％)was in the medical treatment group and 12(34％) in the surgical treatment group.The IL-17 level was significantly correlated with mortality rate after 30 d [odds ratio (OR):1.38;CI:1.14-1.67;P=0.001].The preoperative IL-17 level in the surgical treatment group was 27-7 500 pg/mL(median 2 625 pg/mL),which was significantly higher than mean 156 pg/mL in the medical treatment group.The difference in the area under curve(AUC)between the medical treatment group and surgical treatment group was 0.82(CI:0.74-0.90).The critical value of IL-17 for detection significance was 1 783 pg/mL(sensitivity was 90.5％,specificity was 59.2％).Conclusion Serum IL-17 level is correlated with the mortality rate after 60 d.