Abstract: Objective To understand the mental health and personality characteristics of military medical college students with different major satisfactions. Methods This investigation was conducted in 4 294 military medical college students using a self-designed questionnaire for the students’ general condition including their major satisfactions, Symptom Checklist 90 (SCL-90) and Eysenck personality questionnaires (EPQ). Results The personality and the mental health of the students with different major satisfactions had significant difference. There was significant correlation between the students’ satisfactions toward their majors and the personality and mental health. Conclusion The students with introverted and psychotogenic and neurotic personality are more likely to be dissatisfied with their major, and greater major dissatisfaction may lead to increased mental problems.