Abstract: Objective To compare the mental health state of students in the public middle school with that of the private middle school.Methods By convenience cluster sampling method,1 232 students in two public and two private middle schools in Tai'an city of Shandong province were investigated with Symptom Checklist 90 (SCL-90).Results Of 1 232 anonymous,self-administered questionnaires collected,1 221 were valid ones.The 295 boys and 284 girls were from public middle school,while 344 boys and 298 girls were from private middle school.The rate of minor mental health problems (≥2)of the students from public and private schools was 27.8% and 53.4%,respectively (P<0.01); the rate of major mental health problems (≥3)was 5.2% and 15.4%,respectively (P<0.01).Only the depression factor score was significantly different between the boys of the two type schools (P<0.01).On the contrary,the differences between the girls of the two type schools were prominent in 8 sub-factors except the phobic's factor (P<0.01).Conclusion The mental health problem of students in private school was more serious than that of in public school,and it was especially severe in the girls.More attention should be paid to the students in the private middle schools.