Objective To investigate the early diagnosis value of arterial blood gas analysis , neuron specific enolase and serum glial fibrillary acidic protein in brain injury of premature infant. Methods In the study, 95 premature infants admitted in our hospital were enrolled. 45 premature infants with brain injury were selected as experimental group. 50 premature infants without brain injury were selected as control group. All patients received arterial blood gas analysis , NSE and GFAP on the 1st day and 7th day after birth. Results There is statistically significant difference between the experimental group and the control group on the 1st day after birth in terms of pCO2, pH, BE and lactic acid (P<0.05). In experimental group, there is statistically significant difference between the 1st day and 7th day after birth in terms of pCO2, pH, BE and lactic acid (P < 0.05). The NSE and GFAP levels had statistically significant difference between the experimental group and the control group on the 1st day and 7th day after birth(P < 0.01); the NSE levels of experimental group had statistically significant difference between the 1st day and 7th day after birth (P < 0.05); The GFAP levels of experimental group had statistically significant difference between the 1st day and 7th day after birth (P < 0.01). Conclusion pCO2, NSE and GFAP levels are correlated with brain damage in premature infants in early stage. This could provide evidence of early diagnosis for brain injury in preterm infants.