Abstract:【Abstract】 Objective To observe the changes of color Doppler ultrasonography in fetal detection of abnormal cardiac structure and changes of pulmonary venous flow velocity curve.Methods 1500 pregnant women in our hospital were analyzed. The diagnosis of intracardiac malformation was divided into abnormal group (21 cases), while 21 normal fetuses were randomly selected as normal group. The S peak, D peak, A peak and S/D, S/A, (SA)/D of the pulmonary vein ultrasonography were compared between the two groups.(SA)/D values were analyzed for different intracardiac structures, and their relationship with fetal cardiac structure was analyzed.Results There was no significant difference in Sray and Dpeak between the normal heart and the children with abnormal cardiac structure (P> 005) and there was no significant difference in S/D and S/A between the two groups (P> 005). (SA)/D value was significantly higher than that of normal structure fetus (P<005). Left ventricular hypertrophy (SA)/D value was relatively low. The left ventricular dysplasia fetal (SA)/D value was relatively highest. The different intracardiac malformations of fetal (SA)/D value was significantly different (P<005). Color Doppler ultrasonography missed 1 case of left ventricular dysplasia, simple ventricular septal defect missed 1 case. The missed diagnosis rate of 013%.Conclusion Color Doppler ultrasound can be more accurate diagnosis of fetal heart structure abnormalities. The pulmonary venous flow can be used as an important indicator of observation.