The aim of this study was to examine the relationship among family support, career motivation, and career preparation behavior with university students. In particular, main purpose was to see whether the relationship between family support and career preparation behavior is mediated or not by career motivation. A total of 370 students who were sampled from universities in Jeolla-do and Chungcheongnam-do participated in this study. Three kind of questionnaires were used to collect data on the above 3 variables. Statistical procedures such as correlational analysis, and hierarchical regression were applied for analyzing data. The results of the study were as follows: First, the analysis of correlational relationship between family support, career motivation, and career preparation behavior showed that there was a significant correlation between the variables. Second, the analysis of gender differences in family support, career motivation, and career preparation behavior showed that there was not a significant difference. Third, the career motivation played as a partially mediator while family support had a significant effect on the career preparation behavior. Such results verified that career motivation is a very important mediating variable on the relationship between support of family and career preparation behavior. Finally, the limitation of the study and suggestion for future studies are as follow: First, the measurement method of this study were all collected by self-report questionnaire. Second, In this study, the mediator effect was verified by the hierarchical regression method, but in the subsequent study it is required to analyze the mediating effect more accurately by verifying it with the structural equation model. Third, The other study are required for more synthetic understanding of career preparation behavior. These results can be used to develop programs for university students’ career counseling and career guide.