This study investigated the mediating roles of self-blame and perfectionistic self-presentation on the relationship between socially prescribed perfectionism and social anxiety to form an integrated understanding of the related cognitive mechanisms. A total of 347 undergraduate students completed questionnaires assessing the tendencies of socially prescribed perfectionism, social anxiety, perfectionistic self-presentation, and self-blame. Using structural equation modeling, the results indicated that self-blame and perfectionistic self-presentation sequentially mediated the effect of socially prescribed perfectionism on social anxiety. Additionally, self-blame partially mediated the relationship between socially prescribed perfectionism and perfectionistic self-presentation, and perfectionistic self-presentation partially mediated the relationship between self-blame and social anxiety. Furthermore self-blame demonstrated larger mediating effects than other mediating paths. These findings suggested that interventions to prevent individuals with socially prescribed perfectionism from developing social anxiety symptoms (e,g., compassion-focused therapy) should focus on reducing self-blame and perfectionistic self-presentation. The study’s limitations and future directions for research were discussed.