Objective: To explore the psychological vulnerability in the relationship between stressful life events and psychological crisis, and to provide basis for psychological crisis prevention among college students. Methods: With stratified cluster sampling，3584 students in Weifang Medical University and Weifang University were selected for a crosssectional selfadministrated questionnaire survey in December 2017. A selfdesigned general questionnaire, Adolescent SelfRating Life Events Check List(ASLEC), psychological vulnerability scale, and psychological crisis performance questionnaire for college students were applied in the survey. Mediating effect was tested by using SPSS 23.0 and AMOS 23.0. Results: The average score was 36.53±8.58 for life events(ASLEC), 54.21±11.80 for psychological vulnerability,and 26.33±39.72 for psychological crisis performance. The life events score was positively correlated with psychological crisis score (r=0.54, P<0.05) and positively correlated with psychological vulnerability score(r=0.30, P<0.05); psychological vulnerability score was positively correlated with psychological crisis score(r=0.37, P<0.05). Psychological vulnerability played a partial intermediary role on the relationship between life events and psychological among undergraduates,the effect was 0.10 accounting for 15.13% of the total effect. Conclusion Life events have made a direct influence and an indirect influence mediated by psychological crisis vulnerability on psychological crisis among undergraduates.