Objective To evaluate the diagnostic accuracy and clinical utility of SonoVCADheart， a volume ultrasound-based computer-aided diagnosis system for the fetal heart， in assessing fetal coronary artery morphology compared with conventional fetal echocardiography. Methods A total of 322 high-risk pregnant women in the second and third trimesters were prospectively enrolled between July 2024 and September 2025. All participants underwent both conventional fetal echocardiography and SonoVCADheart imaging. Postnatal echocardiography served as the reference standard. Diagnostic performance for coronary artery origin， course， and luminal diameter was compared between the two modalities. Twenty-two cases were excluded due to inadequate image quality （four-chamber view score ≤ 2）， leaving 300 for final analysis. Results Among the 300 analyzed fetuses， postnatal follow-up confirmed normal coronary anatomy in 278 and abnormalities in 22 （7.33%）， comprising 2 anomalous origins and 20 diffuse dilations （all associated with fetal growth restriction）. SonoVCADheart demonstrated significantly higher overall diagnostic accuracy than conventional echocardiography （P 0.05）. Specifically， SonoVCADheart identified 20 true positives， 2 false positives， 276 true negatives， and 2 false negatives （sensitivity 90.9%， specificity 99.3%）， whereas conventional echocardiography detected 16 true positives， 7 false positives， 271 true negatives， and 6 false negatives （sensitivity 72.7%， specificity 97.5%）. Although sensitivity， specificity， positive predictive value， and negative predictive value were numerically higher for SonoVCADheart， these differences did not reach statistical significance （all P 0.05）. For coronary artery diameter measurements， Pearson correlation coefficients between the two methods were 0.865 for the left main and 0.859 for the right coronary artery （both P 0.05）. Intraclass correlation coefficients （ICCs） were 0.848 and 0.853， respectively， indicating strong inter-method agreement. Conclusions SonoVCADheart provides superior diagnostic accuracy and more reliable quantitative measurements of fetal coronary artery morphology compared with conventional echocardiography. It effectively reduces missed diagnoses and misclassifications， particularly for coronary origin anomalies and secondary dilations， offering valuable support for precise prenatal detection， classification， and clinical management.