Objective:By the investigation of normal and abnormal personality traits of middle school students, we sought to analyze the relationship of them, and to explore the incidence of abnormal personality and gender differences. Methods:The big five personality inventory short version (CBF-PI-B) and personality diagnostic questionnaire version fourth (PDQ-4) had been used to investigate the 1 350 students of middle school students from three different schools in Nanjing, Hefei and Changzhou. Results:(1) Among middle school students, the positive rates of 10 personality disorder subtypes ranged from 3.6% (antisocial) to 41.1% (ocd).There were gender differences of incidence in some personality disorder dimensions. (2) According to the results from the big five personality inventory,significant gender differences were existed in the personality traits of agreeableness, neuroticism and openness.(3) There was a significant correlation between the big five personality traits and personality deviance dimension PDQ-4. Conclusion: The present study suggested that there existed considerable mental health problems related to personality disorders among middle school students and gender differences. The big five personality traits had some correlations with personality disorder trends.