Objective To explore the relationship between urinary activin A and neonatal hypoxic-ischemic encephalopathy(HIE).Methods 50 full-term neonatal with HIE were selected as the observation group,48 normal full-term neonatal in the same period were selected as the normal control group randomly.Within 7 days after birth,the observation group was divided into the group of 30 patients with mild HIE and the group of 20 patients with moderate and severe HIE,according to diagnostic criteria and clinical grading of neonatal HIE.The levels of urinary activin A in two groups after birth at different time(2,12,24,48,72h)was determined by using ELISA method.Results The levels of urinary activin A in moderate and severe HIE group was significantly higher than than in the normal control group(P＜0.01)and mild HIE group(P＜0.01);The levels of urinary activin A in the normal control group and mild HIE group showed no significant differences(P＞0.05).Urinary activin A level＞70 ng/L for the critical value to determine the occurrence of moderate and severe HIE,the sensitivity and specificity of 2 h urinary activin A levels were separately 86％ and 99％;The sensitivity and specificity of 12～72 h urinary activin A levels were separately 100％ and 98％.Conclusion The correlation between the level of urinary activin A and the severity of HIE was positive,the level of urinary activin A had a high degree of sensitivity and specificity for determine the incidence of moderate and severe HIE,it provided an important basis for diagnosis of moderate and severe HIE.