Abstract: Objective To evaluate the development of the cerebral sulci and gyrus and cerebral blood flow in fetuses with tetralogy of Fallot (ToF) in the second and third trimesters using ultrasound imaging. Methods Forty fetuses (23-33+ 6 weeks) with ToF diagnosed using ultrasound imaging between December, 2015 and September, 2016 were analyzed in this study. The development of the cerebral sulci and gyrus was evaluated by measuring the parietal-occipital fissure (POF) depth, POF angle, sylvian fissure (SF) depth, SF width, uncovered insular width, calcarine fissure (CF) depth, hemisphere depth on the views of POF, SF and CF, uncovered insular ratio, biparietal diameter (BPD), and head circumference (HC). Cerebral hemodynamics were assessed by measuring the umbilical artery resistance index, umbilical artery pulsation index, middle cerebral artery pulsation index (MCA-PI), middle cerebral artery resistance index, the cerebral-to-placental resistance ratio, and the cerebroplacental ratio. Results In ToF fetuses, the POF depth, SF depth, CF depth, BPD, HC and hemisphere depth on the views of parietal-occipital sulcus and calcarine sulcus were significantly smaller than those in the control group (P<0.05). The middle cerebral artery resistance index, middle cerebral artery pulsation index, the cerebral-to-placental resistance ratio and the cerebroplacental ratio were also significantly lower in ToF fetuses than in the control group (P<0.05). Conclusion The cerebral sulci and gyrus in ToF fetuses in second and third trimesters show underdevelopment compared with those in normal fetuses, and the changes in hemodynamics caused by abnormal cardiac structure might be one of the reasons for cerebral sulci and gyrus underdevelopment in fetuses with ToF.