Objective: To analyze the application value of ultrasound parameters of umbilical blood flow combined with 24-hour ambulatory blood pressure monitoring in pregnant women with hypertensive disorders of pregnancy (HDP). Methods: From January 2023 to October 2024, 35 pregnant women diagnosed with HDP and treated in the hospital were selected as the observation group. Meanwhile, 35 healthy pregnant women were selected as the control group. The ultrasound parameters of umbilical blood flow and 24-hour ambulatory blood pressure monitoring indicators were compared between the two groups. The correlation between ultrasound parameters of umbilical blood flow and ambulatory blood pressure monitoring indicators was analyzed. The predictive value of combined detection for adverse pregnancy outcome was evaluated. Results: Compared to the control group, pulsatility index (PI), resistance index (RI), and systolic/diastolic ratio (S/D ratio) were higher, and peak systolic velocity (PSV) was lower in the observation group (P<0.05). The 24-hour pulse pressure (24hPP), 24-hour systolic blood pressure (24SBP), 24-hour diastolic blood pressure (24DBP) and blood pressure variability (BPV) were higher, and the rate of nocturnal blood pressure decline was lower in the observation group (P<0.05). Pearson correlation analysis showed that PI, RI, and S/D ratio were positively correlated with ambulatory blood pressure monitoring indicators in the observation group (P<0.05). PSV was negatively correlated with ambulatory blood pressure monitoring indicators (P<0.05). The receiver operating characteristic (ROC) curve analysis showed that the area under the curve (AUC) of combined detection for predicting adverse pregnancy outcome (0.852) was greater than that of each umbilical blood flow parameter or ambulatory blood pressure (0.732, 0.721). Conclusion: There are significant differences in ultrasound parameters of umbilical blood flow and 24-hour ambulatory blood pressure monitoring indicators between healthy pregnant women and pregnant women with HDP. There’s a significant correlation between ultrasound parameters of umbilical blood flow and ambulatory blood pressure monitoring indicators in pregnant women with HDP. Moreover, combined detection of the two can significantly improve the accuracy of prediction of adverse pregnancy outcome.