Abstract: Objective: To evaluate the diagnostic value of IL-6 and TNF- alpha levels in cord blood and peripheral blood of premature infants.Methods: Thirty-nine premature infants diagnosed as early onset sepsis were selected as the observation group and 53 non-septic premature infants admitted to hospital at the same time as the control group. Relevant clinical data were collected. The levels of IL-6 in cord blood and peripheral blood were measured by ELISA. ROC curves of cord blood and peripheral blood IL-6 in the diagnosis of sepsis were made to explore the significance of cord blood and peripheral blood IL-6 in the diagnosis of premature infants with early onset sepsis. Result：The birth weight of septicemia group was lower than that of non-septicemia group, and the time of premature rupture of membranes was earlier. The incidence of eating less, crying less, moving less, abdominal distention and skin blossom in septicemia group was higher than that in non-septicemia group. The levels of lactate, total bilirubin, C-reactive protein, IL-6 in umbilical cord blood and peripheral blood of septicemia group were higher than those of non-septicemia group. The ROC curve showed that the AUC of IL-6 in cord blood was 0.757, 95% CI (0.651-0.863), the threshold value was 17.6 pg/ml, the sensitivity was 56.4%, and the specificity was 94.3%. AUC of IL-6 in peripheral blood was 0.768, 95% CI (0.665-0.871), the threshold was 2.05pg/ml, the sensitivity was 69.2%, and the specificity was 83.0%. Conclusion: The levels of IL-6 in cord blood and peripheral blood were significantly higher in the early stage of sepsis, which may have clinical significance in the diagnosis of premature infants with early-onset sepsis. Conclusion: The level of IL-6 in cord blood increased significantly in the early stage of sepsis, which may have clinical significance in the diagnosis of premature infants with early-onset sepsis.