Objective：To explore the correlation between postoperative（PO） cerebral oxygen saturation（SctO2） and clinical outcomes in children after congenital heart surgery. Methods：A prospective cohort study was conducted in 65 patients who underwent congen－ital heart surgery with cardiopulmonary bypass and admitted to intensive care unit（ICU） afterwards from December 2016 to October 2017 in our hospital. The PO SctO2 within the first 24 hours was measured consecutively by near-infrared spectroscopy（Fore-sight，P/N01-06-2030C，CASmed，USA）. The nadir of SctO2（nSctO2） and the mean of SctO2 （mSctO2） were analyzed with adverse outcome（AO） （low cardiac output syndrome，cardio-pulmonary resuscitation or death），the pediatric risk of mortality Ⅲ（Prism Ⅲ） score of PO 24 hours，the maximum of vasoactive-inotropic score of PO 24 hours（VISmax），the duration of mechanical ventilation，and length of ICU stay. Results：２６ cases（40.00%） were divided into AO group，while the other 3９ cases（60.00%） were divided into non-AO group. The nSctO2 and mSctO2 were significantly lower in AO group than those in non-AO group [44.00% （32.00% to 47.25%） vs. 56.00%（50.00% to 60.00%），P=0.000；61.94%（58.95% to 65.15%） vs. 70.00%（66.67% to 73.76%），P=0.000]. The nSctO2 and mSctO2 were negatively correlated with the Prism Ⅲ score（rs=-0.653，P=0.000；rs=-0.593，P=0.000），the VISmax（rs=-0.346，P=0.005；rs=-0.422，P=0.000），the duration of mechanical ventilation time（rs=-0.424，P=0.001；rs=-0.519，P=0.000） and the length of ICU（rs=-0.407，P=0.000；rs=-0.528，P=0.001），respectively. ROC analysis indicated a cutoff point of 51.50% of nSctO2 in the first 24 hours to predict AO（AUROC=0.849，P=0.000），95%CI=0.756 to 0.942，with a sensitivity of 92.30% and a specificity of 74.40%. Conclusion：Both the amplitude and duration of SctO2 drop in the PO 24 hours were correlated with the poor clinical outcomes. SctO2 lower than 51.50% in PO 24 h may potentially act as a predictive factor.