Abstract: The age of 3-6 years is a period of rapid development. As a substantial proportion of childhood life, sleep is inextricably linked to the development of their cognitive function, especially attention. The current study investigated the relationship between sleep quality and attention in 138 preschool children through questionnaires and the attention task. Furthermore, we examined whether bedtime routines would moderate the association between sleep and attention. The findings suggested that: (1) The negative effects of sleep problems on the attentional function of preschoolers arise mainly from sleep restriction and erratic daily sleep duration. (2) Listening to stories before bedtime reinforces the impact of sleep duration issues on attention, making it easier for children to benefit from high-quality sleep. The findings of this study provide a reference for parents to reasonably cultivate their children's sleeping habits and promote children's sleep health and cognitive development.