Objective To investigate the characteristics on the time of sunshine exposure in Chinese primary and middle school students.Methods A total of 43 771 primary and middle school students were randomly selected from 12 provinces in China.A self-reported questionnaire was used to understand their time of sunshine exposure on weekdays and weekends as well as related family information and behaviors.x2 test was used to compare the hours of sunshine exposure among different groups.Multivariate logistic regression analysis was conducted to identify the influencing factors.Results Results from the current survey indicated that the average time of sunshine exposure on weekdays and weekends were 2.49 and 3.22 hours,respectively.On weekdays,proportions of students with time of sunshine exposure ≤2 h/d or ＞2 h/d were 60.81％ and 39.19％,respectively.On weekends,the proportions became 44.05％ and 55.95％,respectively.On weekdays,the time of sunshine exposure as ≤2 h/d was significantly different among factors as sex,urban or rural area,residential area,self-rating academic performance,type of housing or ways of commuting to school.On weekends,the time of sunshine exposure ≤2 h/d were significantly different among sex,residential areas,self-rating academic performance,type of housing and ways of commuting to school.Data from the multivariate logistic regression analysis showed that the limited sunshine exposure was significantly associated with factors as:type of primary schools,being girls,students living in the urban area or living in central or western areas,with normal or better academic performances,living in a fiat apartment and the time spent on watching video program ＞2 h/d both on weekdays and weekends.Conclusion The time of sunshine exposure seemed not enough among school students and significant differences were seen among different groups.