Abstract: Objective To investigate the personality trait and its effect on mental health among the soldires in combat troops.Methods A total of 1 435 soldiers were enrolled in this study.Symptom Checklist-90(SCL-90)and Eysenck Personality Questionnaire(EPQ)were used in the survey.Results The total score of SCL-90 in the soldiers was 123.17±37.90,with a positive rate of 26.2%.The score was 8.13±2.33 for psychoticism(P),10.76±0.34 for extroversion(E),10.28±4.47 for neuroticism(N),and 10.19±2.18 for concealment tendency(L),respectively.The score of P in the soldires showed a positive skew distribution and the N score and L score a negative skew distribution.The score of E showed a normal distribution.The mean of P was significantly higher than the norm of Chinese people and Chinese soldiers(P<0.001 for all).The mean of L was significantly lower than the norm of Chinese people and Chinese soldiers(P<0.001 for all).The mean of E was significantly lower than the norm of Chinese soldiers but significantly higher than that of Chinese norm(P<0.001).The mean of N was significantly lower than the norm of Chinese soldiers(P<0.05),but was not significantly different from the norm of Chinese people.The scores of P and N in SCL-90 were negatively correlated with each SCL-90 dimension score and total score(P<0.001).The results of regression analyses showed that psychoticism and neuroticism were the important personality trait influencing the mental health among the soldiers(F=123.46,P<0.01).ConclusionPersonality trait affect mental health of the soldiers in combat troops significantly.Trainning and developing sound personality is a effective way to maintain mental health.