Objective To investigate the value of fetal pulmonary vein (PV) blood flow parameters in the assessment of left ventricular diastolic function in pregnancy induced by gestational hypertension (HDCP). Methods 137 cases (disease group) of HDCP admitted to our hospital from July, 2017 to November, 2018 were selected, including 49 cases of pregnancy hypertension (group A), 46 cases of mild preeclampsia (group B), 42 cases of severe preeclampsia (Group C), 40 cases of healthy pregnant women (control group) were selected from our hospital during the same period. The blood flow parameters of PV in each group were compared, including peak atrial systolic velocity (A), peak ventricular systolic velocity (S), peak ventricular diastolic velocity (D), pulmonary vein pulsation index (PI), peak pulmonary vein velocity index (PVIV) after ultrasound examination. The PV blood flow parameters of asphyxiated fetus of the disease group were compared. Results The peak flow rate of A of the disease group was lower than that of the control group, and the values of PI and PVIV were higher than those of the control group, the differences were statistically significant(P < 0.05); The peak velocity of AA decreased of the group A, B and C (P < 0.05), PI and PVIV increased of the group A, B and C (P < 0.05), and there was significant difference between the two groups (P < 0.05); Pearson correlation analysis showed that the peak velocity of A of the disease group was negatively correlated with PI and PVIV (r = -0.724, - 0.639, P < 0.05); 26 cases of neonatal asphyxia occurred of the disease group after birth There was no asphyxia in the other 111 cases (no asphyxia group). The peak velocity of A of the asphyxia group was lower than that of the non asphyxia group (P < 0.05), and the values of PI and PVIV were higher than that of the non asphyxia group (P < 0.05). Conclusion The detection of PV blood flow parameters can early understand left ventricular diastolic function of HDCP fetus and provide basis for early clinical intervention.