Objective:To investigate the value of determining serum diamine oxidase in early diagnosis and grading of the hypoxic ischemic encephalopathy (HIE)and early evaluation of HIE combined with intestines barrier function injury. Methods : Serum DAO activities were measured in 41 neonates of full-term HIE during the first three days of life. Each patient’s clinical grading was assessed at 7 days after birth

and 9 healthy neonates in the same period were randomly chosen as control group. Results:The serum DAO in HIE group group were (11.456±2.227)U/ml

significantly higher than ( 6.277±2.431 ) U/ml in control group ( P<0.01 ) .With increase of clinical degree

serum DAO gradually increased ( P<0.01 ) . The abnormal rate of serum DAO of severe HIE group was 92.9%

significant higher than 63.0% in mild group ( P<0.05 ) . The abnormal rate of serum DAO in Light-For-Dates infants were 80.0%

higher than 55.6% in severe HIE group of infants appropriate for gestational age (P <0.05). Conclusion:Measurement of serum DAO at 3 days after birth is valuable in early diagnosis and grading of HIE and early evaluation of HIE combined with Intestines barrier function injury.