To investigate the influencing factors of non-suicidal self-injury (NSSI) in patients with depressive disorder. Methods: Quantitative analysis and closed questionnaires were used to investigate outpatients and inpatients with depressive disorders. According to the evaluation results of the Patient Health Questionnaire-9 (PHQ-9), the 17-Item Hamilton Rating Scale for Depression (HAMD-17) and the 14-Item Hamilton Rating Scale for Anxiety (HAMD-14), the patients enrolled were divided into non-NSSI group and NSSI group, with 60 cases in each group. The general demographic information, depression and anxiety (HAMA score and HAMD score), presence or absence of suicidal idea, parental and peer attachment questionnaire (father-child trust, mother-child trust, father-child communication, mother-child communication, father-child alienation, and mother-child alienation) scores, and Experiences in Close Relationships Inventory (ECR) scores were compared between groups. The influencing factors of NSSI in patients with depressive disorder were analyzed based on the final results. Results: There were significant differences between the two groups in terms of HAMA score (t=20.256), HAMD score (t=16.854), suicidal idea (χ 2 =14.903), parental and peer attachment (t= 4.075, 6.542, 4.520, 6.941, 7.565, 8.593), and ECR attachment distribution (χ2 =5.546) (OR=4.875, 3.440, 2.508, 3.997, 2.374, 1.360, 3.445, P=0.001, 0.028, 0.035, 0.025, 0.031, 0.038, 0.029). Correlation analysis and Logistic regression analysis showed that HAMA score, HAMD score, suicidal idea, parent-child attachment, and adult attachment were main influencing factors of NSSI in patients with depressive disorder (P<0.05). Conclusion: Patients with depressive disorders have relatively severe NSSI. Depression and anxiety, suicidal idea, parent-child attachment and adult attachment are main influencing factors.