Objective: to explore the characteristics of adolescent self-disclosure with peers and its relationship with loneliness. Method: using the Questionnaire of Adolescent Self-Disclosure with Peers, UCLA Loneliness Scale, and the subjects were 400 college students of Wenzhou medical college. Results: (1) There existed significant differences in college students' self-disclosure with different kinds of peers. There were significant grade differences in college students' self-disclosure with best same-sex friends and best opposite-sex friends. (2) College students' self-disclosure with best same-sex friends in anticipation and money, and that with best opposite-sex friends in interest and intimate friendship, could significantly predict loneliness. College students' self-disclosure with best same-sex friends, self-disclosure in interests, physical development/sex and school experience, and that with best opposite-sex friends in physical development/sex, school experience and anticipation, could significantly predict intimate relationship. Conclusions: There existed a correlation between adolescent self-disclosure with peers and loneliness.