The purpose of this study was to testify the relationship of parental psychological control perceived by young adults in twenties and their social anxiety, and the mediating effects of internalized shame and ambivalence over emotional expressiveness in the model. The online questionnaires were administered to 350 young adults in twenties to assess the four major variables(parental psychological control, internalized shame, ambivalence over emotional expressiveness and social anxiety). In correlation analysis, parental psychological control, social anxiety, internalized shame and ambivalence over emotional expressiveness were positively correlated. Bootstrapping method was used to test the mediating effects, and this study here is statistically significant revealing the path of parental psychological control to social anxiety by mediator such as internalized shame and ambivalence over emotional expressiveness. Finally, parental psychological control-social anxiety partial mediator model was supported. As a result of the study, the higher the level of parental psychological control, the higher the level of internalized shame and ambivalence over emotional expressiveness, and subsequently the higher the level of social anxiety in twenties. The implication and limitation of this study, and future tasks were discussed.