The purpose of this study was to investigate the relationship among lifestyles, personal relationship (friendship and romantic relationship), and living behaviors shared with closed friends and romantic friends. The study undertook a quantitative research of university students' living behaviors in the private residence. A survey questionnaire was employed with three hundred and eighty-four students living in the private residence nearby their universities. Reliability of the questionnaire was 0.93. The significance was tested by Pearson's Product Moment Correlation Coefficient. Results indicate that there was a positive relationship at a low level between friendship and romantic relationship, between students' lifestyle and friendship, between students' lifestyle and romantic relationship, between friendship and living behaviors shared with closed friends and between romantic relationship and living behaviors shared with closed friends. There was no significant difference between friendship and living behaviors shared with romantic friends, however, there was a negative relationship at a moderate level between romantic relationship and living behaviors shared with romantic friends. Results show that friendship was developed to romantic relationship, and students' lifestyle in the private residence had an effect on friendship and on romantic relationship. Moreover, different types of personal relationship could explain living behaviors shared with closed friends, but could not explain living behaviors shared with romantic friends. The development of relationship asserts the necessity for educators to give a careful look when students lived in the private residence and work proactively with owners of the private residence by using two-way communication to build mutual understanding and trust to get their participation to create constructive lifestyles and living behaviors to students.(Contains 5 tables.)