Objective: To explore the relationship between parents’ unstable marital status and offspring’s suicide attempts and the possible mediating factors, and to provide reference for suicide prevention among off spring grom unst able families. Methods: From 2017 to 2018, 2 766 valid questionnaires were collected from freshmen in a university in Hunan province. Students completed questionnaires of childhood trauma and depression traits,and reported their parents’ marital status and suicide attempts etc. Results: Compared to college students with parents of stable marital status,students with parents of unstable marital status showed higher reported rate of suicide attempts and higher scores of depression trait and childhood trauma (t/χ2=2.78, 5.83, 20.30, P<0.05). Controlling possible confounding factors,unconditional Logistic regression showed that childhood trauma,unstable marital status of parents and depressive traits were positively correlated with suicide attempt(OR=1.05, 1.45, 1.08, P<0.05). The 95% confidence interval of the Bootstrapping method with four mediation pathways (parental marital status→childhood trauma→depressive trait,childhood trauma→depressive trait→suicide attempt,parental marital status→childhood trauma→suicide attempt and parental marital status→childhood trauma→depressive trait→suicide attempt) does not include zero. Conclusion Childhood trauma and depressive traits mediate the relationship between parental instable marriage and suicide attempts in off spring.