Abstract： Objective To assess the application value of high time-resolved MR angiography (TR-MRA) in postoperative follow-up study of children with congenital heart diseases. Methods Seventy-three patients (median age 6 years, range 1-20 years) with congenital heart diseases who underwent TR-MRA scan after operation were retrospectively analyzed. Twenty-nine cases also were performed conventional contrast-enhanced MRA and forty-four cases were performed phase-contrast MRA. A 3D T1-weighted fast gradient-echo sequence was used for time-resolved three-dimensional MRA (10-20 dynamic data sets, less than three seconds per dynamic data set). The flow dynamics and morphology of pulmonary circulations, lung perfusion and collaterals flow direction were noted. All imaging quality was evaluated by using 5 scales. Left and right pulmonary artery flow volumes were measured and left and right pulmonary artery ratio was noted. SPSS22.0 was used in statistic analysis. The statistical analysis of comparing imaging quality was performed by using paired t-test. The intermodality agreement between TR-MRA and phase contrast in assessing left and right pulmonary perfusion was tested by Kappa coefficient. Results In 73 cases, imaging scores were over 3 and imaging quality was good enough for diagnosis. In 29 cases, there was no statistic difference between TR-MRA and conventional CE-MRA in demonstrating great vessels (P>0.05) except that CE-MRA scores(3.77 ± 0.39)was higher than TR-MRA scores(3.44 ± 0.55)of <br> inferior vena cava (IVC). There was statistic difference(t=3.68,P=0.01)between two sequences. TR-MRA could qualitatively demonstrate the pulmonary perfusion comparing to the results of PC. In PC sequence, there were 8 cases with symmetric and 36 cases with asymmetric left and right pulmonary perfusion. In TR-MRA sequence, there were 6 cases with symmetric and 38 cases with asymmetric left and right pulmonary perfusion. There was an excellent agreement between PC and TR-MRA (Kappa=0.83,P=0.01). Conclusions TR-MRA not only supplies with high spatial resolution imaging which demonstrates postoperative great arteries anatomy and also with high temporal resolution imaging which can demonstrate the preferential or balanced pulmonary blood flow and collaterals flow direction. TR-MRA is a very important sequence in follow-up study of congenital heart disease.