Correlation was sought between serum intestinal fatty acid binding protein (I-FABP), blood routine examination indexes, and necrotizing enterocolitis (NEC) disease classification. According to Bell-NEC grade, 86 children with NEC were divided into mild group (46 cases) and severe group (40 cases). Serum I-FBAP and blood routine indices including white blood cells (WBC), platelets (PLT), neutrophils and lymphocytes were determined. Serum levels of I-FABP and WBC in severe group were higher than those in mild group (both p <0.001), and serum level of PLT was lower than that in mild group (p <0.001). NEC grade was positively correlated with I-FABP and WBC (r=0. 930, p <0.001; r=0. 946, p <0.001), negatively correlated with PLT (r=-0. 602, p <0.001), and had weak correlation with neutrophils and lymphocytes (r=0. 186, p=0. 087; r=0. 072, p=0. 509). In conclusion, serum levels of I-FABP, WBC and PLT were correlated with the severity of NEC in children, which could be used as a reference index to judge prognosis of NEC children.