The purpose of this study is to investigate the influence of perceived parental attachment and self-differentiation on the adjustment to college life For this study, we used research data about the adjustment to college life, perceived parental attachment and self-differentiation which were collected from 271 university students live in Busan. We carried out correlation analysis to see the relationship between perceived parental attachment, self-differentiation and the adjustment to college life. Also, we carried out stepwise multiple regression to predict the most influential variable in college life. Results of this study were as follows. First, perceived parental attachment, and self-differentiation have a meaningful positive relationship with college life. Second, attachment anxiety, attachment avoidance, family projection, and cognitive and emotional functioning have more effects on the adjustment to college. Especially attachment avoidance affects college life more than others. These results show the importance of a wide variety of policy research to develope peer support program and counseling for a better school life on schools, classes, counseling centers.