Objective: To investigate the association between subthreshold depression, psychotic like experiences (PLEs), and their interactions with non suicidal self injury (NSSI) in adolescents from Shandong, so as to provide a reference for the prevention and early intervention of NSSI in adolescents. Methods: A random cluster sampling method was used to select a total of 6 090 adolescents aged 13-22 from two cities along the coast and inland of Shandong Province. Electronic surveys were administered using the SelfInjurious Behavior Questionnaire, Community Assessment of Psychic Experiencepositive 8 items(CAPE-P8), and the Center for Epidemiological Studies Depression Scale(CES-D). The relationship between subthreshold depression, PLEs, and their interaction with NSSI was analyzed using multivariate Logistic regression. Results: The detection rate of NSSI among adolescents was 21.3%. The highest NSSI reporting rate (27.9%) was found in the age group of 13-15 years.The NSSI reporting rates for those detected with subthreshold depression and PLEs were 49.9% and 30.7%, respectively. Multivariate analysis indicated that individuals with subthreshold depression were 3.47 times more likely to engage in NSSI [OR(95%CI)=3.47(2.68-4.50)]. Those identified with PLEs had 5.32 times higher risk of engaging in NSSI than those without such experiences [OR(95%CI)=5.32(4.10-6.89)]. When both subthreshold depression and PLEs coexist, the risk of engaging in NSSI was 18.47 times higher than in individuals with neither condition [OR(95%CI)=18.47(14.75-23.13)] (P<0.01). The relative excess risk due to interaction (RERI), attributable proportion (AP), and synergy index (S) were 11.44, 0.61, and 2.89, respectively, indicating that the combined interaction of subthreshold depression and PLEs accounted for 61% of adolescent NSSI. Conclusions Subthreshold depression and psychoticlike experiences are associated NSSI in adolescents and exhibit an additive interaction. Alleviating subthreshold depression in adolescents and reducing psychotic experiences may play a positive role in preventing the occurrence of NSSI.