Abstract： Objective To design an approach for automatic detection of nuchal translucency(NT) of fetus in ultrasound images based on digital image visual features via computer technology.Methods The established approach for digital image visual feature-based automatic detection of NT of fetus in ultrasound images consisted of image retrieval,connected component extraction,target assessment and measurement of NT.Results of automatic NT measurement were obtained from standard experimental images(n=35),clinically screened images (n=1208) and artificially marked images (n=120).The accuracy and bias of positioning were examined and maximal errors were recorded.Results The accuracy of NT positioning was 100％(35/35),90.7％(1096/1208)and 90.8％(109/120) corresponding to standard experimental images,clinically screened images and artificially marked images via automatic measurement respectively.An error of less than 0.03 mm was found.Conclusion The approach for automatic measurement of NT of fetus in ultrasound images based on digital image visual feature is successful established,which can reduce the subjectivity and randomness of manual operation and improve accuracy of ultrasound screening.