Objective: To explore relationship among bullying victimization, psychological traits and suicide ideation of middle school students, and to provide suggestions for school bullying and suicide prevention for adolescents. Methods: A total of 3 635 students of 7-9th grade from 5 junior middle schools were enrolled and investigated with the Olweus Bully/Victim Questionnaire (OBVQ), psychological traits questionnaire for middle school students and suicide ideation questionnaire. Results: Prevalence of bullying victimization was 28.34% of middle school students, while the prevalence of verbal, relational and physical bullying were 22.59%, 12.05% and 7.54%, respectively. Boys had significantly higher rates of bullying victimization than girls (χ2=88.92，94.29，7.69，P<0.01). Bullying victimization was positively associated with suicidal ideation (r=0.21, P<0.01), while associated with psychological traits (r=-0.17, -0.22, P<0.01). Psychological traits had a moderating effect on the relationship between bullying victimization and suicidal ideation (β=-0.04, P<0.05). Conclusion Psychological traits can buffer the adverse effects of bullying victimization on suicidal ideation, and the critical role of psychological traits in the maintenance and development of adolescent mental health should be emphasized.