BackgroundUnintentional injuries among children and adolescents are a major public health problem worldwide. These injuries not only have negative effects on children’s physiology and psychology, but also bring huge economic losses and social burdens to families and society. Unintentional injuries are the leading cause of disability and death among Chinese adolescents, and left-behind children (LBC) are more prone to experience unintentional injury. The purpose of this study was to evaluate the type and incidence of unintentional injury among Chinese children and adolescents and explore the influences of personal and environmental factors by comparing the differences between LBC and not left-behind children (NLBC).MethodsThis cross-sectional study was conducted in January and February 2019. Additionally, 2786 children and adolescents from 10 to 19 years old in Liaoning Province in China were collected in the form of self-filled questionnaires, including Unintentional Injury Investigation, Unintentional Injury Perception Questionnaire, Multidimensional Subhealth Questionnaire of Adolescent (MSQA), Negative life events, “My Class” questionnaire and Bullying/victim Questionnaire. Multiple logistic regression analysis was used to explore the factors associated with unintentional injury among children and adolescents. Binary logistic regression analysis was used to explore the factors affecting unintentional injuries between LBC and NLBC.ResultsThe top three unintentional injuries were falling injuries (29.7%), sprains (27.2%) and burns and scalds (20.3%) in our study population. The incidence of unintentional injuries in LBC was higher than that in NLBC. Burn and scalds, cutting injury and animal bites in LBC were higher than those in NLBC. The results show that junior high school students (odds ratio (OR) = 1.296, CI = 1.066–1.574) were more likely to report multiple unintentional injuries than primary school students. Girls (OR = 1.252, CI = 1.042–1.504) had higher odds of reporting multiple unintentional injuries. The odds of multiple injuries in children and adolescents with low levels of unintentional injury perception were higher than those in children and adolescents with high levels of unintentional injury perception (OR = 1.321, C = 1.013–1.568). Children and adolescents with a higher levels of mental health symptoms (OR = 1.442, CI = 1.193–1.744) had higher odds of reporting multiple unintentional injuries. Compared with teenagers who had never experienced negative life events, teenagers who had experienced negative life events many times (OR = 2.724, CI = 2.121–3.499) were more likely to suffer unintentional injuries many times. Low-level discipline and order (OR = 1.277, CI = 1.036–1.574) had higher odds of reporting multiple unintentional injuries. In-school adolescents who were bullied were more likely to report being injured multiple times than their counterparts who were not bullied (OR = 2.340, CI = 1.925–2.845). Low levels of unintentional injury perception, experienced negative life events and bullying had greater impacts on LBC than on NLBC.ConclusionThe survey found that the incidence of at least one unintentional injury was 64.8%. School level, sex, unintentional injury perception, subhealth, negative life events, discipline and order and bullying were associated with incidents of unintentional injury. Compared with NLBC, LBC had a higher incidence of unintentional injury, and special attention should be given to this group.