<p>Perceived ostracism is significantly related to individuals’ lower self-compassion, but its intermediate mechanisms are still unclear. The current study aimed to explore the relationship between perceived ostracism (T1) and self-compassion (T2) and their underlying mechanisms. In the present study, a longitudinal survey was adopted, including two rounds of data collection. In the first round, 675 participants were recruited, and after 6 months, the second round was conducted with 617 participants recruited. The attrition rate was 8.59%, and there were 617 valid participants (64.7% female). The moderated mediation model was applied to verify the mediating role of rumination (T2) between perceived ostracism (T1) and self-compassion (T2), and the moderating role of childhood maltreatment (T2) in the mediation model. After controlling for gender, results demonstrated that perceived ostracism (T1) significantly and negatively predicted self-compassion (T2); rumination (T2) mediated the relationship between perceived ostracism (T1) and self-compassion (T2); and childhood maltreatment (T1) moderated the direct pathway between perceived ostracism (T1) and self-compassion (T2), as well as the latter pathway of the mediating effect of rumination (T2). The study results supported all core hypotheses, and the moderated mediation model was established.</p>