Emerging evidence implicates that built environment is involved in regulating sleep timing. However, few studies have examined multiple exposures, and the combined effects remain unexplored. Based on merging of geospatial imaging with dataset derived from a cross-sectional survey conducted in Shanghai, China during April through June 2019, our analyses were performed among 16,814 children aged 3-12 years, with a specific focus on bedtime. Four built environment measures, including artificial light at night (ALAN), vegetation indicator of the normalized difference vegetation index (NDVI), road density, and building density, were quantified. A Composite Built Environment Exposure Index (CBEEI) was constructed, with higher CBEEI representing greater urbanization and lower green coverage. Generalized linear and logistic models were established, along with tests for modification effects, stratification differences, and supplementary verification via machine learning models. It was observed that higher NDVI was associated with earlier bedtimes (β = -0.080 on weekday and -0.056 for free-day; both p < 0.001), whereas greater levels of ALAN, road density, and building density correlated with later bedtimes (weekday β ranged from 0.030 to 0.099 and free-day β ranged from 0.025 to 0.080; all p < 0.001). CBEEI had a stronger association with later bedtime than any individual components. Each quartile increase in CBEEI correlated with bedtimes that were 0.154 h later (95 % CI: 0.138-0.169) on weekdays and 0.124 h later (95 % CI: 0.103-0.144) on free-days. Generally, these associations demonstrated a dose-dependent pattern and were modified by population characteristics, particularly age and sleep duration. Similar relationships were observed when bedtimes were analyzed as dichotomous variables, and machine learning methods provided corroborative support. Our findings indicated that children living in neighborhoods with low greenness, high urbanization, and especially their co-exposure, tended to have later bedtimes, which emphasizes the coordinated strategies in urban planning to promote healthy sleep in children.