Abstract: Study on the psychological structure of undergraduates' integrity has great important significance in cultivating their integrity quality. This article adopts mental lexical assessment method to discuss the psychological structure of Chinese undergraduate' integrity. With explorative factor analysis, the results indicate that integrity contains six major dimensions, which consist of positive facets (honesty, uprightness and trustworthiness) and negative facets (trickiness, sophistication, untruthfulness). Moreover, the results show that the structure possesses predictive reliability and validity. Therefore, this construction can be used as the basis for future researches about integrity.