Objective To explore the independent effects of personality traits and social support on depressive traits and states in adolescents， and the regulatory effects of stressful life events on depressive traits and states in adolescents. Methods A total of 303 students from one middle school in Sichuan Province were recruited from July 2022 to August 2022 by convenience sampling method. All the participants were investigated online with Adolescent Self-Rating Life Events Check List （ASLEC）， Chinese Big Five Personality Inventory brief version （CBF-PI-B）， Social Support Rating Scale （SSRS）， Trait Depression Scale （T-DEP）， and The Center for Epidemiological Studies Depression Scale （CES-D）. Information of adolescent stress related life events， personality traits， social support， depression traits， and depression status were collected. Multiple linear regression analysis was used to investigate the impact of personality traits and social support on adolescent depressive traits and states， and the interaction between personality traits and social support in the impact of stressful life events on adolescent depressive traits and states was analyzed. Results The results of multiple linear regression showed that there was a negative correlation between open personality traits and adolescent depression traits （β=-0.17， 95%CI=-0.27- -0.08， P＜ 0.05）， and a negative correlation between social support and adolescent depression traits （β=- 0.16， 95%CI=-0.21- -0.10， P＜ 0.05） and depressive state （β=- 0.13， 95%CI=-0.19- -0.07，P ＜ 0.05）. The results of interaction showed that open personality played a regulatory role in the influence of life events on the adolescent depressive trait （P＜ 0.05）， while social support played a regulatory role in the influence of life events on the adolescent depression state （P＜ 0.05）. Conclusions For adolescents， higher open personality leads to a lower depressive trait， and higher social support leads to both a lower depressive trait and a lower depressive state. Open personality and social support respectively play a regulatory role in the impact of stressful life events on the depressive traits and states.