Abstract: Objective To investigate the correlation between different fetal ultrasound parameters and neonatal adverse outcomes in the third trimester and its application value in predicting neonatal adverse outcomes. Methods A retrospective analysis of 300 pregnant women who underwent routine prenatal ultrasound examination and finally delivered in our hospital from January 2017 to May 2018 was divided into adverse outcome group and no adverse outcome group according to whether there were adverse outcomes in neonates. The value of ultrasound detection indicators in predicting neonatal adverse outcomes. Results The incidence of gestational hypertension, gestational diabetes, and gestational subclinical hypothyroidism was higher in the adverse outcome group than in the non-adverse outcome group (all P<0.05). The fetal middle cerebral artery and umbilical artery S/D values in the third trimester pregnancy group were higher than those without adverse outcomes (all P<0.05). The fetal thyroid volume and fetal physical and physical scores in the adverse outcome group were significantly different from those without adverse outcomes (all P<0.05);Multivariate analysis showed that hypertensive disorder of pregnancy, fetal thyroid volume, umbilical artery S/D value, and middle cerebral artery S/D values were the relevant factors leading to neonatal adverse outcomes (all P<0.05). The sensitivity was 82.11% and the specificity was 41.83%. The sensitivity of umbilical artery S/D was 74.44% and the specificity was 51.22% in predicting neonatal adverse outcome. The sensitivity of thyroid volume in predicting neonatal adverse outcome was 66.70%, specificity is 46.35%. Conclusion The umbilical artery S/D value>2.975 and thyroid volume>0.424 in the fetal blood flow parameters and thyroid parameters in the third trimester can be used as an early evaluation index for predicting neonatal adverse outcomes in the third trimester.