This paper explored the relationship between personality disorder and personality traits from the perspective of gender differences. This paper adopted the principle of convenient sampling. A questionnaire survey was conducted among the undergraduates in Nanjing. SPSS 23.0 and Mplus software were used to carry out t-test, regression analysis and mediation effect analysis. Results: (1) The score of female avoidance personality disorder was significantly higher than that of male, While the score of schizoid, narcissistic and antisocial personality disorder was significantly lower than that of male. In the multi-dimensional trait model, there are gender differences in the five characteristics and the 25 characteristics. (2) In female samples, personality disorder was associated with negative affectivity, antagonism and anxiousness, deceitfulness, and callousness. And in the male sample, personality disorder was associated with negative affectivity, detachment, disinhibition, and Separation insecurity, hostility, perseveration, suspiciousness, intimacy avoidance. (3) The degree of education of the father played a part of the intermediary effect between the antagonism and the personality disorder. (4) The interaction of deceitfulness and callousness plays an inverse role in personality disorder. Conclusion: There are gender differences in personality disorder and personality traits.