To explore the effects of parental warmth or rejection on non-suicidal self-injury (NSSI) in high school students. Methods: A total of 454 high school students were enrolled. The Short-Egna Minnen av Barndoms Uppfostran (s-EMBU-c), Adolescent Non-suicidal Self-injury Assessment Questionnaire (ANSAQ), Revised Inventory of Parent and Peer Attachment (IPPA-R), Self-Concept and Identity Measure (SCIM), and Hospital Anxiety and Depression Scale (HADS) were administered. Results: The overall detection rate of non-suicidal self-injury was 22.7% . There were statistically significant differences in the detection rate of non-suicidal self-injury in terms of only-child status (χ 2 =21.19，P<0.001) and family residence ( χ 2 =13.04，P<0.001). Peer attachment and identity formation exerted a mediating effect on the relationship between parental warmth or rejection and non-suicidal self-injury. Conclusion: Parental warmth and rejection can affect non-suicidal self-injury in high school students both directly and through the chain-mediating effects of peer attachment and identity formation.