Objective To investigate the value of echocardiography and multi-slice spiral CT in the diagnosis of complex congenital heart disease(CCHD).Methods 73 children with CCHD were selected and diagnosed by echocardiography and multi-slice spiral CT in Children''s Hospital of Shanxi Province from April 2012 to April 2016.The distribution of disease types in 73 children with CCHD was recorded,and the diagnostic accuracy of multi-slice spiral CT was compared with echocardiography,multi-slice spiral CT and echocardiography.Results 73 children with CCHD had a total of 172 cardiac malformations confirmed by operation and pathology.By segment analysis,there were 30 cases of extracardiac vascular malformations,52 cases of abnormal heart and vascular connection,90 cases of atrial and atrioventricular junction deformity.Multislice spiral CT was performed to detect 155 cases of cardiac malformations,including 28 cases of extracardiac malformation,48 cases of maligant heart and great vessels,79 cases of intracardiac and atrioventricular malformation.Echocardiographic diagnosis of 158 cases of cardiac malformations,including 28 cases of extracardiac vascular malformations,49 cases of large vascular malformations,81 cases of intracardiac and atrioventricular junction deformity.Echocardiography combined with multi-slice spiral CT in the diagnosis of 167 cases of cardiac malformations,including 29 cases of extracardiac vascular malformations,50 cases of large vascular malformations,88 cases of intracardiac and atrioventricular malformation.The diagnostic accuracy between echocardiography [91.86％(158/172)] and multislice spiral CT [90.12％(155/172)] had no significant difference (P＞0.05).The diagnostic accuracy of echocardiography combined with multi-slice spiral CT was 97.09％(167/172),which was higher than 91.86％(158/172) of echocardiography and 90.12％(155/172) of multislice spiral CT,the difference was statistically significant(P＜0.05).Conclusion The echocardiography combined with multi-slice spiral CT in the diagnosis of CCHD has high accuracy,it can provide strong imaging support for surgical options and prognosis.