The purpose of this study is investigating the mediating effect of Career maturity and Social support in the relation between Family strength and Depression of University students. Participants of this study were 300 University students who attended school at that time. SPSS 22.0 and AMOS were used for statistical analysis. The main results of this study are as followings. First, Family strength has negative correlation with Depression. Second, Social support has positive correlation with Family strength, and Social support has negative correlation with Depression. Third, Career Maturity has positive correlation with Family strength, and Career Maturity has negative correlation with Depression. Fourth, Social support has complete mediated effect in the relation between Family strength and Depression. So, when a counselor meets a client who has low Family strength and High Depression, the counselor needs to be a Social support system for the client.