Objective: To explore the effect of dialectical behavior therapy (DBT) on cognitive emotion regulation in adolescents with non suicidal self injury (NSSI), so as to provide reference for improving the cognitive and emotional well being of NSSI adolescents. Methods: A total of 166 adolescents with non suicidal self injury who were hospitalized in the Department of Child and Adolescent Psychiatry of the Second Affiliated Hospital of Xinxiang Medical University from March 2021 to March 2023, were selected by the convenient sampling method. According to the random number table method, participants were divided into the experimental group and the control group, with 83 cases in each group. The control group was given routine nursing, while the experimental group was given dialectical behavior therapy on the basis of routine nursing. The 8 week intervention was conducted once a week, with 45- 60 minutes each time. The control group and the experimental group were evaluated with Hamilton Anxiety Scale (HAMA), Hamilton Depression Scale (HAMD) and Cognitive Emotion Regulation Questionnaire (CERQ) before and after the intervention. Statistical analysis was conducted using t test and χ 2 test. Results: Before the intervention, there was no significant difference in the scores of each scale include HAMA, HAMD and CERQ between the experimental group and control group ( P >0.05). The scores of HAMD (13.58±3.24, 33.02±7.59), HAMA (12.41±2.51, 24.25±7.14), adaptive adjustment strategy score (69.20± 11.97 , 60.51±7.29) and nonadaptive adjustment strategy scores (37.43±7.87, 47.87±5.20) of CERQ, significantly changed after 8 weeks of intervention ( t=-21.46, -14.25, 5.57, -10.08, P <0.01). Conclusions Dialectical behavior therapy can improve the anxiety, depression and cognitive emotion regulation of adolescents with NSST. Active intervention should be taken to regulate the emotions of adolescent with NSSI and reduce the occurrence of NSSI.