Objective To investigate the value of the Doppler flow spectrum of uterine artery and internal iliac artery in the second trimester of normal pregnancy in predicting adverse pregnant outcome. Methods Forty-six pregnant women with bilateral notch uterine arterial blood flow otherwise normal who were performed fetal echocardiography in Tangdu Hospital from May 2020 to December 2021 in the second trimester were collected as the case group and 51 normal pregnant women as the control group. The ratio of systolic to diastolic peak blood flow velocity (S/D), pulsatility index (PI), resistance index (RI), and peak systolic blood flow acceleration time (IIA-AT), internal diameter, and blood flow volume (IIA-Q) of the uterine artery and internal iliac artery in pregnant women were obtained by color Doppler ultrasound.To compare the difference of the above blood flow parameters between the two groups and analyze the detection rate of uterine artery and internal iliac artery blood flow parameters for adverse pregnancy outcomes.Results Compared with the control group, uterine artery S/D, PI, RI in the notch group were significantly increased, IIA-AT was significantly prolonged, and the difference was statistically significant (all P<0.05). The detection rate of the early diastolic notch of uterine artery combined with IIA-AT and IIA-S/D for adverse pregnancy outcomes (50.0%) was higher than that of the early diastolic notch of uterine artery alone (19.6%), especially for preeclampsia, the difference was statistically significant (P<0.05).Conclusion The early diastolic notch of uterine artery combined with the blood flow spectrum parameters of internal iliac artery in the middle pregnancy period can better detect the occurrence of adverse pregnancy outcomes, which can provide an objective basis for early clinical diagnosis and treatment.