Abstract
Depression has become a major burden of mental illness in our young people，and shows an increasing trend year by year. Relevant research has demonstrated that adverse life events serve as significant risk factors for depression among college students. Few research has been conducted on the underlying mechanisms through which negative life events influence depression in college students，and no relevant researches have been carried out for vocational undergraduates. A survey was conducted among 1457 vocational undergraduates using four instruments: The Adolescent Self-Rating Life Events Checklist (ASLEC), Intolerance of Uncertainty Scale-12(IUS-12), The Career Decision-making Difficulties Questionnaire (CDDQ), and Patient Health Questionnaire-9 (PHQ-9). Findings showed that the depression detection rate of vocational undergraduates was 53.6%. The findings suggest that negative life events have a dual impact on depression, both directly and indirectly through three distinct pathways: (1) the independent mediation of intolerance of uncertainty(IU), (2) the independent mediation of career decision-making difficulty(CDD), and (3) the serial mediation of IU and CDD. Increasing their tolerance to uncertainty and resolving difficulties in making career decisions may help to alleviate their depression symptoms.