Objective To explore the early changes of cerebral blood flow in premature infants with hypoxic-ischemic encephalopathy (HIE).Methods The peak systolic velocity (Vs),end diastolic velocity (Vd),and resistance index (RI) of middle cerebral artery (MCA),anterior cerebral artery (ACA),lenticulostriate artery (LA),and frontal intermediomedial artery (FIA)were detected in 86 premature infants with HIE by color Doppler within 20 - 24 hours after birth.The results were compared with those from 88 control subjects.Results The blood flow velocity increased significantly within 20 - 24 hours after birth in both groups,as compared with the baseline.Vd of FIA was significantly greater in the HIE group than in the control group.There was no significant difference in RI between the HIE group and the control group within 20-24 hours after birth.Conclusions A compensatory change of cerebral blood flow develops in premature infants with hypoxic-ischemic encephalopathy within 20 to 24 hours after birth,but this change has to be compared with the baseline to determine its significance.