Abstract: Objective To explore emotional and behavioral problems among the left-behind middle school children in rural areas of Fujian province.Methods A self-designed questionnaire for children's conditions and Strengths and Difficulties Questionnaire(SDQ)(the edition for students)were used to investigate 2 483 middle school students(including 963 left-behind students)from villages and towns of 9 cities or counties in Fujian province.Results The prevalence of emotional and behavioral problems among the left-behind children and non left-behind children was 7.3% and 7.6%,respectively,without significant difference between the two groups.The prevalence of conduct problems,peer problems,and prosocial problems among the male left-behind children was 9.2%,10.2%,and 11.5%,which were significantly higher than 5.1%,6.9%,and 8.0% among the female left-behind children;while the prevalence of emotional symptoms among the female left-behind children was 9.1%,which was significantly higher than 3.5% among the male left-behind children.The prevalence of total difficulties,emotional symptoms,and hyperactivity among the left-behind children living with relatives other than parents or friends were 13.6%,11.7%,and 18.4%,which were significantly higher than 6.0%,5.4%,and 5.4% among those living with one parent and also higher than 6.7%,5.3%,and 10.8% among those living with grandparents.The children with longer time of left-behind had more emotional problems and those with less time contacting with their parents had more conduct problems.Living with relatives other than parents or friends(OR=1.270)was a risk factor for psychopathology,while good family economic condition(odds ratio=0.479)was a protective factor.Conclusion The left-behind children in Fujian province showed good mental health status,and those living with at least one parent or grandparent,left behind for a short time,keeping frequent contact with parents,and with good familial economic conditions had less emotional and behavioral problems.