This study aimed to investigate the predictive value of the vasoactive-inotropic score (VIS) at different time points for postoperative prolonged mechanical ventilation (PMV) in adult congenital heart disease patients undergoing surgical treatment combined with coronary artery bypass grafting. Patients were divided into two groups that developed PMV or not. The propensity score matching method was applied to reduce the effects of confounding factors between the two groups. VIS at different time points (VIS at the end of surgery, VIS6h, VIS12h, and VIS12h max) after surgery were recorded and calculated. The value of VIS in predicting PMV was analyzed by the receiver operating characteristic (ROC) curve, and multivariate logistic regression was used to analyze independent risk factors. Among 250 patients, 52 were in the PMV group, and 198 were in the non-PMV group. PMV rate was 20.8%. After propensity score matching, 94 patients were matched in pairs. At each time point, the area under the ROC curve predicted by VIS for PMV was > 0.500, among which VIS at the end of surgery was the largest (0.805). The optimal cutoff point for VIS of 6.5 could predict PMV with 78.7% sensitivity and 72.3% specificity. VIS at the end of surgery was an independent risk factor for PMV (odds ratio=1.301, 95% confidence interval 1.091~1.551, P<0.01). VIS at the end of surgery is an independent predictor for PMV in patients with adult congenital heart disease surgical treatment combined with coronary artery bypass grafting.