The purpose of this study was to investigate the relationship between personality traits and moral identity of college students and the moderating effect of legal consciousness on it. The Legal Consciousness Scale, Moral Identity Scale and Big Five Personality Inventory were surveyed among 1878 college students. The results of the study showed that: 1) Moral identity and legal consciousness were significantly positively correlated with conscientiousness, agreeableness, openness, and extroversion, while significantly negatively correlated with neuroticism. 2) Personality traits, moral identity, and legal consciousness showed significant gender differences. Also, there was a significant gender difference in the influence of conscientiousness on moral identity. 3) Legal consciousness negatively moderated the influence of conscientiousness and agreeableness on college students’ moral identities. Therefore, our findings imply that the individuality of personality traits should be respected; and, professional cultivation of law education and legal consciousness should be implemented in tertiary education to improve an individual’s moral identity.