Objective：To investigate the clinical value of the third-generation dual-source CT prospective ECG-gated sequence scan－ning mode in the diagnosis of complex congenital heart disease. Methods：A total of 43 patients who were clinically diagnosed with complicated congenital heart disease and underwent surgery were enrolled，and the results were used as the gold standard to compare the detection rate and overall diagnostic efficacy of heart dual-source CT prospective ECG-gated sequence scanning and echocardio－graphy. Results：A total of 187 deformities were found in 43 patients after surgery；155 deformities were detected by dual-source CT，and 153 were detected by echocardiography；the overall detection rates of dual-source CT and echocardiography were 82.89% and 81.82%，respectively（ ?字２=0.074，P=0.786）. For deformities at cardiovascular junctions，dual-source CT had a detection rate of 100% and echocardiography had a detection rate of 90.91%（ ?字２=2.095，P=0.148）；for intracardiac malformations，dual-source CT had a detection rate of 62.35% and echocardiography had a detection rate of 81.18%（ ?字２=7.430，P=0.006）；for pericardial vascular malfor－mations，the detection rates of dual-source CT imaging and echocardiography were 100% and 80.00%，respectively，and there was a significant difference between the two methods（ ?字２=17.778，P=0.001）. Third-generation dual-source CT had a positive predictive val－ue of 98.05%，a negative predictive value of 96.43%，an accuracy of 96.64%，a specificity of 99.69%，and a sensitivity of 80.75%，and echocardiography had a positive predictive value of 99.35%，a negative predictive value of 96.52%，an accuracy of 96.90%，a specificity of 99.90%，and a sensitivity of 81.28%. Conclusion：Compared with echocardiography，dual-source CT imaging has obvi－ous advantages in the diagnosis of pericardial vascular malformations in complex congenital heart disease. There is no significant dif－ference in overall detection of lesions between dual-source CT imaging and echocardiography.