Although social media has become a platform for users to produce, collaborate and share content, increasing self-disclosure has also increased the risk of individuals suffering from cyberbullying. As repetitive harm, humiliation, harassment and other acts to other individuals or groups by means of network technology, cyberbullying has become one of the most common social problems in the world, but research on the victims of cyberbullying is obviously insufficient. This study builds a model of the impact of attachment anxiety on cyberbullying with social media self-disclosure as a mediating variable from the perspective of the actual victims, and explores the mediating role of social media self-disclosure in this relationship. Using an empirical method, 845 Chinese college students were surveyed online by the attachment anxiety scale, social media self-disclosure scale, and cyberbullying victim scale. SPSS was used for data processing, reliability and validity test, correlation analysis, regression analysis and mediation effect test. The results show that attachment anxiety positively affects cyberbullying; attachment anxiety positively affects social media self-disclosure; social media self-disclosure plays a part of the mediating role between attachment anxiety and cyberbullying. The results of this study reveal the influence mechanism of online bullying victims, which helps to remind attachment anxiety individuals to pay attention to the possible harm of cyberbullying caused by their self-disclosure behavior in the process of using social media. At the same time, this study is of great significance to further develop methods to reduce cyberbullying.