Objective To explore the effect of coping style on mental health of junior midddle school students. Methods A total of 786 Tibetan students from junior middle school were investigated by General Data Questionnaire,Simplified Coping Style Questionnaire and Mental Health Inventory of Middle-school students Scale. Results The hierarchical regression analysis indicated that the demographic variables including grade,boarding or not,family income,left-in-home,grades,academic performance got into the equation(F=8.526,P=0.000),and after controlling demographic variables,the coping style explained 21.7% variance of the mental health scores independently. Conclusion School managers should especially focus on the Tibetan junior middle school students who are in grade one and left-in-home,with low family income,poor academic performance and improve the overall level of mental health among junior middle school students by increasing their positive coping and reducing the negative coping styles.