objective To investigate the correlation between hemodynamic changes in middle cerebral artery (MCA) and prognosis of premature infants within 3 days after birth.Methods Middle cerebral artery systolic peak flow velocity(PSV),end diastolic velocity(EDV),pulsatility index (PI)and resistance index(RI)were detected by color doppler flow image in 3 days after birth.The prognosis of premature infants was followed up and observed. According to the neuropsychological development assessment results of children aged 0 to 6 months after birth,they were divided into two groups:the developmental quotient<85 was divided into the poor prognosis group, and the developmental quotient ≥85 was divided into the good prognosis group.Results MCA-PSV and MCA-EDV of preterm infants in the group with poor prognosis within 3 days after birth were significantly lower than those in the group with good prognosis,and MCA-PI and MCA-RI group with poor prognosis were higher than those in the group with good prognosis,with statistically significant differences(P<0.05).The sensitivity of MCA-PSV,MCA-EDV and MCA-RI to predict poor prognosis of premature infants was 3.9%,9.8% and 52.9%,respectively.The specificity was 98.6%,97.2% and 72.2%,respectively. Conclusion The application of color doppler ultrasound to determine the blood flow parameters of middle cerebral artery in 3 days after birth of premature infants has certain clinical value for predicting premature infants,providing valuable basis for early clinical intervention.