Objective To investigate the application value of dynamic three-dimensional ultrasound in diagnosis of fetal malformations. Methods One hundred and fifty fetus in late pregnancy were scanned by two-dimensional and dynamic three-dimensional ultrasound. Their diagnostic rate and postnatal diagnostic rate were compared. Results In 150 fetuses,there were 31 mslformations in 26 cases, two-dimensional ultrasound diagnosis was consistent with postnatal diagnosis in 19 cases, compliance rate of 61.3%. Dynamic three-dimensional ultrasound diagnosis was consistent with postnatal diagnosis in 28 cases ,compliance rate of 90.0% , there was significant difference between the two methods (P0.05). Conclusion Compared with two-dimensional ultrasound,dynamic three-dimensional ultrasound could not only exactly provide three dimensional anatomy structures, but also clearly demonstrate direct stereo image.It is more accurate in diagnosis of malformations of face and limbs.