"Research Findings:" Sustained attention is a fundamental cognitive function for young children's development. We investigated the effects of school-based audiovisual game training with parental involvement on sustained attention (SA) in 5-6-year-old Chinese children. Totally 75 children and their parents participated and were assigned into three groups. The School Practice Intervention (SPI) group and the Parental Involvement Intervention (PII) group underwent an eight-week audiovisual game training, while the No Intervention (NI) group participated in regular activities and received no intervention. We tested participants' visual and auditory sustained attention at four time points, i.e., pretest, middle test, posttest, and follow-up test. Results indicated that (1) children in PII and SPI groups had significantly greater visual and auditory sustained attention than the NI group in posttest and follow-up test; (2) the PII group showed better SA than the SPI group in posttest and follow-up test; (3) visual SA of experimental groups improved significantly since the middle test, while the improvement of auditory SA emerged since posttest. "Practice or Policy:" The play-based audiovisual training in a school setting effectively enhances SA for 5-6-year-olds, and parental involvement benefits the intervention. More efforts should be made to improve auditory sustained attention. The educational implications of these findings were discussed.