BackgroundPsychological problems among children and adolescents have become a public health issue. This study aimed to investigate associations between screen time (ST), outdoor activity (OA), and emotional and behavioral health problems (EBHPs) among South Chinese children and adolescents.MethodsA total of 30,188 boys and girls from 14 elementary and junior high schools on six streets in Shenzhen were included in this study. EBHPs were measured with the strengths and difficulties questionnaire; OA and ST data were obtained through self-reporting. Descriptive analyses, chi-square tests, and logistic regressions were performed using SPSS 23.0.ResultsIn our study, 42.4% students had insufficient OA, 24.2% students had excessive ST, the abnormal prevalence of emotional symptoms, conduct problems, peer problems, hyperactivity problems, prosocial behavior, and total difficulties scales were 18.5%, 6.9%, 6.4%, 13.1%, 10.7% and 8.8%. There were significant associations between ST/OA, independent and addictive interaction, and EBHPs among children and adolescents. Participants with high exposure to ST were more likely to have EBHPs than those with low exposure; participants with low exposure to OA were also more likely to have EBHPs than those with high exposure. The interactive associations of ST and OA on EBHPs were stronger than those of ST or OA individually.ConclusionsOur results show positive associations between ST, OA, and EBHPs. They indicate that interventions should be considered for decreasing ST and increasing OA in children and adolescents.