Abstract： Objective To explore the clinical value of prospective electrocardiography-triggering high-pitch spiral acquisition by dual-source CT (HP mode ) in children with congenital heart diseases (CHD).Methods Thirty-six patients ( mean age:0.67 years,range:1 month to 2 years and 6 months; 25 males;mean weight:7.7 kg)underwent prospective ECG-triggering high-pitch spiral acquisition.The dose length product (DLP) was recorded to calculate effective dose ( ED ).Two experienced radiologists made diagnosis and assessed the overall image quality by a five-point scale independently.The consistency of their judgment was determined by Kappa statistics.Surgeries were performed in 29 patients,and conventional cardiac angiography(CCA) was performed in 7 patients.The accuracy,sensitivity and specificity of HP mode were calculated based on the surgical or CCA findings.Results The DLP was (5.12 ± 1.64) mGy.cm with a range of 2.4 mGy · cm to 9.2 mGy · cm and ED was (0.125 ± 0.027 ) mSv ranging from 0.078 mSv to 0.179 mSv.The average subjective image quality score was 4.2 ± 0.7.All images were diagnosable.Two radiologists made good agreement ( K =0.774,P ＜ 0.05 ).The accuracy,sensitivity and specificity of HP mode were 98.9％,94.2％ and 99.8％,respectively.Conclusion Low radiation dose with the accurate diagnosis of anomalies makes HP mode a new choice for children with CHD.