The present study expands on previous research regarding the correlation between parental overprotection (POP) and non-suicidal self-injury (NSSI) in Chinese adolescents. Drawing from self-determination theory, the study aims to investigate the mediating effect of psychological need satisfaction on the relationship between POP and adolescent NSSI, as well as the potential moderating effect of anger expression. A sample of 1248 adolescents (Mage = 13.34 years; SD = 0.96 years) completed anonymous questionnaires to measure the study variables. The results of the regression analysis indicate that: (1) the positive link between POP and adolescent NSSI is mediated by low psychological need satisfaction; (2) this indirect relationship is particularly pronounced in adolescents who report high levels of anger expression. These findings suggest that psychological need frustration may serve as a mechanism linking POP to adolescent NSSI, and that adolescents who tend to express more anger may be at an increased risk for engaging in NSSI. Systemic family therapy is recommended for clinicians and consultant to help them better understand the adolescents with NSSI in overprotective family system and adopt targeted intervention programs.