Objective To investigate the mental health of the guarded students and personality differences between the guarded students and the non-guarded students. Methods Stratified sampling method was used to draw 278 secondary school students in Chongqing city.They were investigated with MHT,Eysenck Personality Questionnaire (child). Results 1) Among the 278 students in rural area,the detection rate of mental disorder was 6.5%.2) The guarded students had significant higher scores than the non-guarded students over MHT and the factors of self-blame(42.8±1.4,33.4±1.7,t=3.52;6.1±0.2,4.5±0.3,t=3.58,all P<0.01).3) The guarded students scored significantly higher than the non-guarded students over the factors of EPQ related to psychoticism(P),neuroticism(N) (5.64±3.21,3.29±2.68,t=4.307;15.61±4.53,8.73±4.71,t=7.355,all P<0.01),The guarded students scored significantly lower than the non-guarded students on the factors of EPQ related to lie(L) (10.50±4.29,13.04±4.54,t=-2.828,P<0.01).4) The factors in MHT positive correlated with the factors of psychoticism and neuroticism.The factors in MHT had negative correlation with the factors of EPQ related to lie(L).5)The factors of Personality explained 21%~49% difference of the scores of MHT,study anxiety,hostility,interpersonal sensitivity,body symptom,hypersensitiveness.The neuroticism(N) best forecasted and explained the score of MHT. Conclusions Mental health problems of the guarded students in rural areas are serious.There are personality differences between the guarded students and the non-guarded students.Personality is the important factor on mental health of guarded students,and these differences call for special attention.