Objective: To explore the health-related quality of life (HRQoL) of children and adolescents with simple congenital heart defects before and after the transcatheter intervention. Methods: The Pediatric Quality of Life Inventory 4.0 scale was used to assess the quality of life of 78 children and adolescents before and after the transcatheter intervention and to evaluate the parents' perception of their children's quality of life. Results: In all, 76 patients were completed the study. The results showed that the scores of the four dimensions and the total score for the quality of life of the patients significantly improved 1 month after the intervention. At 6 months after treatment, the scores in all dimensions continued to improve. From the parents' perspective, the scores of the patients in all dimensions improved significantly at 1 month and 6 months after treatment. In terms of the quality of life assessment, the self-assessment results of the patients were more positive than those of their parents. Conclusions: The results showed that the quality of life of children and adolescents with simple congenital heart defects can be positively affected by the transcatheter intervention. Moreover, this improvement is not transient and seems to increase over time.