Abstract: Objective To explore influencing factors of mental health among lef-tbehind children in rural area.Meth ods Overall 748 school children of grade four to six were selected randomly from 5 prmiary schools and investigated with a questionnaire and Mental Health Test(MHT)using cluster stratified sampling.Results Between male and female left-behind children,significant differences were observed in phobic symptom and total score of anxiety tendency(P < 0.05). 72.5% of the children were cared by their mothers,20.9% by grandparents,1.4% by fathers,and 5.2% by others.10.8% of guardians of the children were illiteracy,40.4% with prmiary school education,34.4% with middle school,and 14.4% with high school and above.Among the children,there were signficant differences in study anxiety,self-blame tendency, phobic symptom and total score of anxiety between the children under guardians with different education level(P < 0.05). The children with longer tmie of parents working outside had significant higher scores of self-blame tendency,body symptom,and impulsion tendency(P < 0.05).Conclusion Among the left-behind children in rural area,the schoolgirls,the children under guardians with lower education,and the children with longer tmie of parents working outside hometown hav e more mental health problems.