BACKGROUND: The psychological researches on undergraduates popularly believe that status of mental health of undergraduates can be worried.OBJECTIVE: To investigate the relationship between personality and mental health of undergraduates in Henan province, and analyze the feasible value of developing mental health education effectively.DESIGN: Sampling investigation.SETTING: Department of Health Administration, Henan Medical College for Staff and WorkersPARTICIPANTS: 1 128 students from 3 university and colleges in Henan province, whose majors were agriculture, medical science, sciences,literal arts, arts and physical education, etc., were enrolled randomly in this study between April and June 2001.METHODS: Group test was performed in 1 128 students from higher learning schools of Henan province test with Eysenck Personality Questionnaire (EPQ) [including 4 dimensions: Extraversion (E), Neuroticism (N),Psychoticism (P), and Social Desirability (L)] and Symptom Checklist90(SCL-90) (90 items, 9 dimensions).MAIN OUTCOME MEASURES: ① Comparison of personality characteristics between undergraduates and national norms. ② Classified comparison of personality characteristics of undergraduates. ③ Relationship between personality characteristics and mental health of undergraduates.RESULTS: Incomplete questionnaires were excluded, and 1 100 qualified questionnaires were collected. ① Comparison of personality between undergraduates and national norms: Scores on N and L of EPQ in male undergraduates were higher significantly than those of the national norms (5.47 ±3.13,4.53 ±3.11 ;4.99 ±2.47,4.50 ±2.59,P ＜ 0.001 ).Scores on N, P and L of EPQ in female undergraduates were all higher remarkably than those of the national norms (2.97±1.71,2.68±1.82;5.68±3.08,4.97±2.96;5.32±2.46,4.74±2.48,P ＜ 0.05-0.001). ②Classified comparison of personality in undergraduates: There were obvious differences on the 4 dimensions of EPQ in students of 6 different specialties (P ＜ 0.05-0.001 ). Scores on P in agricultural students were the highest (3.44±1.97); Scores on E in students of physical education were the highest (8.27±2.45), while scores on N in literate arts students were highest (5.99±3.24). Male students'scores on L were lower markedly than female students'(4.99±2.47,5.32±2.46,P ＜ 0.05).Scores on E in students from cities were lower significantly than those in students from countrysides (7.54±2.73,7.93±2.63,P ＜ 0.05). Between lower grade (freshman year and sophomore year) and higher grade (junior year and senior year), only scores on L in the former were high er significantly than those in the latter (5.42±2.44,5.01±2.48,P ＜ 0.01 ).Moreover, scores on E in student cadres were higher apparently thanthose in non-student cadres (8.42±2.61,7.42±2.68,P ＜ 0.001). ③Relationship of personality and mental health in undergraduates: E and L of personality dimension in undergraduates had obviously negative correlation with every factor of SCL-90 (P ＜ 0.01-0.001 )while N had significant positive correlation with every factor of SCL90 (P ＜ 0.001),and P had significant positive correlation with somatization, hostility,phobic anxiety and paranoid ideation (P ＜ 0.05-0.01 ).CONCLUSION: Personality of undergraduates have extremely close internal correlation with their mental health. Introversion, emotional instability and psychoticism of personality of undergraduates have side effects on their psychological health. There are some differences of personality characteristics in different specialty, sex, grade, native place (city or countryside),cadre or non-cadre students.