Abstract: Objective To determine the significance of the biochemical indices of intestinal barrier function (D-Lactate, Diamine oxidase (DAO) and endotoxin) in Bell stage of neonatal necrotizing enterocolitis (NEC)Methods Retrospective collection and analysis of data from 78 infants suffered from NECAnd, 32 normal neonates were selected as control group. According to the Bell stage, the infants with NEC were divided into three groups, NEC I (44 cases, 56. 41%), NEC II (28 cases, 35. 90%) and NEC III (6 cases, 7. 69%). JY-DLT intestinal barrier function analysis system were used to detect the serum indices of intestinal barrier function (lactic acid, diamine oxidase and endotoxin D), and combined with other laboratory index (WBC, PLT, CRP and PCT) to evaluate the significance in NEC.Results (1) The relationships between common laboratory indicators and Bell stage of NEC:① The lever of WBC, CRP and PCT in NEC were higher than normal new born, but PLT was lower (P < 0. 05). ② The WBC increased with the Bell stage of NEC, but there was no significant difference between the three groups (P> 0. 05). ③ PLT increased with the Bell stage of NEC, and PLT of NEC III was significantly lower than NEC I and NEC II (P < 0. 05). However, there was no significant difference between NEC I and NEC II (P> 0. 05). ④ CRP in serum increased with the Bell stage of NEC, and CRP in NEC I was significantly lower than the other two groups (P < 0. 05). However, there was no difference between the NEC II and NEC III (P> 0. 05). ⑤ Similarly, PCT in serum also increased with the Bell stage of NEC, and PCT in NEC I was significantly lower than the other two groups (P < 0. 05). However, there was no statistical difference between the NEC II and NEC III groups (P> 0. 05). (2) The relationships between the serum indices of intestinal barrier function and Bell stage of NEC:(① The lever of D-Lactate, DAO and endotoxin in serum in NEC were higher than normal new born (P < 0. 05). ② D-Lactate, DAO and endotoxin increased with the Bell stage of NEC, and there were significantly differences between all groups (P < 0. 05).