Objective To perform the amplitude integrated electroencephalogram (aEEG) for neonates with asphyxia, and to analyze the correlation between aEEG score and hypoxic-ischemic encephalopathy (HIE) severity, so as to provide reference for early clinical diagnosis of HIE and severity assessment. Methods A retrospective analysis was conducted on 88 cases of asphyxia neonates with gestational age ＞35 weeks who were admitted to the Neonatal Department of Nanjing Maternity and Child Health Hospital from July 2014 to December 2020 and underwent bedside Cerebral Function Monitor(CFM) examination within 12 hours after birth.The neonates were divided into normal group (n=10), mild HIE group (n=30), moderate HIE group (n=32) and severe HIE group (n=16).The risk factors of severe HIE were analyzed.Compressed aEEG recordings were obtained by CFM examination and four parameters of aEEG patterns were evaluated and scored, including continuity(Co), cycling(Cy), amplitude of lower border(LB), bandwidth span and amplitude of lower border(B), and the total score(T) was added up.The correlation between each parameter and HIE severity was analyzed.After HIE cases were treated with hypothermia, cerebral function was reviewed and the aEEG scores of each group were compared again.Fifty-five babies completed cranial MRI examination, and the difference of MRI severity among HIE groups was compared. Results There were significant differences in gestational age, pH value of the first postnatal blood gas analysis between the severe HIE group and other HIE groups(H=11.104, F=3.725, P＜0.05).The cesarean section rate in normal group was higher than that in other groups (Fisher's exact probability, P=0.031).The lower scores of Co, Cy, LB, B and T of aEEG indicated more severe HIE, and the negative correlation was significant (r=-0.531, -0.529, -0.423, -0.468, -0.487, P＜0.05).After HIE cases were treated with hypothermia, aEEG scores among each group were significantly improved.But the aEEG total score of the severe HIE group was still significantly different from that of the mild and moderate HIE groups (F=5.972, P<0.001).There was no significant difference in MRI severity among different HIE groups(P＞0.05). Conclusions aEEG scoring system can early diagnose and predict the severity of HIE in asphyxia neonates with brain function monitoring, which can be used as a tool to evaluate the severity of HIE.Hypothermia therapy can improve the cerebral function of HIE patients.