Abstract: Objective To explore the factors affecting the mental health of the middle school students left-in-home,and to provide educational strategies.Methods 279 left-in-home students form three middle schools in Jiangxi province were involved in the survey.They were made to take the Mental Health Diagnostic Test(MHT)and accept investigation about daily life.Results Using anxiety scores as the dependent variable in regression analysis,it was found that the independent variables including sex,feeling of going home,relationship with classmates,degree of parents'caring,the person to whom telling private secrets and whet her being at grade eight entered into the regression equation(F=8.562,P=0.000).Standardized regression coefficient of the variables was-0.304(P=0.000),-0.202(P=0.004),-0.178(P=0.006),-0.149(P= 0.030),-0.147(P=0.022),-0.125(P=0.049),respectively.Conclusion There is a lot of factors influencing mental health of middle school students and educators should take some educational measures to help them.