Objective To explore the application value of ultrasound Doppler blood flow parameters in the diagnosis of fetal hypoxia.Methods A total of 60 pregnant women admitted to Jinxi County People's Hospital from January 2021 to June 2023 were selected,including 30 pregnant women with fetal hypoxia(study group)and 30 normal pregnant women(reference group).Both groups of pregnant women were examined by ultrasound Doppler after admission.The pulsatility index(PI),resistance index(RI)and the ratio of peak systolic blood flow velocity to end diastolic blood flow velocity(S/D)of fetal umbilical artery and middle cerebral artery were compared between the two groups,and the PI,RI and S/D of middle cerebral artery with different gestational weeks and different degrees of hypoxia were analyzed.Results The PI,RI and S/D values of umbilical artery in the study group were higher than those in the reference group,and the differences were statistically significant(P<0.05).The PI,RI and S/D values of the middle cerebral artery in the study group were lower than those in the reference group,and the differences were statistically significant(P<0.05).The PI,RI and S/D values of middle cerebral artery in 37-40 weeks and>40 weeks were lower than those in 32-36 weeks,and the differences were statistically significant(P<0.05).The PI,RI and S/D values of fetal middle cerebral artery in severe hypoxia were lower than those in mild hypoxia,and the differences were statistically significant(P<0.05).Conclusion The application value of ultrasonic Doppler blood flow parameters in the diagnosis of fetal hypoxia is high,which can provide an effective reference for clinical treatment.