BackgroundPrevious studies on subgroups of adolescent non-suicidal self-injury （NSSI） behaviors have predominantly focused on community and school-based samples， with limited research on clinical samples. The precise identification of clinically distinct NSSI subgroups in adolescents is critical for optimizing medical resource allocation. ObjectiveTo explore the subgroups of NSSI in adolescent outpatients， and to provide references for intervening of NSSI behaviors. MethodsFrom May 2021 to April 2022， 192 adolescents who met the NSSI diagnostic criteria as outlined in the Diagnostic and Statistical Manual of Mental Disorders， fifth edition （DSM-5） were recruited from psychiatry or psychology clinics at 6 hospitals in Fujian Province. Participants were assessed using the Adolescent Non-suicidal Self-injury Assessment Questionnaire （ANSAQ）， the Childhood Trauma Questionnaire （CTQ）， the Depression Anxiety Stress Scale-21 item（DASS-21） and the Difficulties in Emotion Regulation Scale （DERS）. Latent profile analysis was conducted using Mplus 8.0. ResultsA total of 192 adolescents with NSSI behaviors completed the study， and the analysis yielded three subgroups of self-injurers： the mild self-injury group （50 cases， 26.04%）， the emotional disorder group （81 cases， 42.19%）， and the severe self-injury group （61 cases， 31.77%）. There were significant differences in the total scores of CTQ， DASS-21 and DERS among the three groups （F=8.058， 51.414， 48.742， P<0.01）. The severe self-injury group exhibited significantly higher scores in CTQ， DASS-21 and DERS when compared to both the mild self-injury group and the emotional disorder group （P<0.05）. Moreover， the emotional disorder group also reported notably higher DASS-21 and DERS scores in comparison to the mild self-injury group （P<0.05）. ConclusionClinical studies on adolescent outpatients engaging in NSSI behaviors reveal three distinct typological profiles， mild self-injury， emotional disorder-related self-injury， and severe self-injury. ［Funded by Fujian Social Science Planning Project （number， FJ2019B173）］