Abstract Background Both excessive screen time and early screen exposure have been linked to children’s health outcomes, but few studies considered these two exposures simultaneously. The aim of this study was to explore the independent and interactive associations of excessive screen time and early screen exposure with health-related quality of life (HRQOL) and behavioral problems among Chinese children attending preschools. Methods A cross-sectional study of 4985 children aged between 3 and 6 years was conducted in Chengdu, China. Each parent has finished an online questionnaire regarding their children’s screen use, HRQOL, and behavioral problems. Children with screen time over 1 h/day were considered as having excessive screen time. Early screen exposure was defined if the children had started using screen-based media before the age of 2 years. HRQOL was assessed by the Pediatric Quality of Life Inventory version 4.0 (PedsQL 4.0), while behavioral problems were confirmed with the 48-item Conners’ Parent Rating Scale (CPRS-48). Results Of the 4985 children (2593 boys and 2392 girls) included, the mean age was 4.6 (SD: 1.0) years. After adjustment for confounders and early screen exposure, excessive screen time was significantly associated with worse HRQOL scores in all dimensions and summary scales, as well as each type of behavioral problems (all p values