This paper, based on Social Psychology, explores how such things as prejudice and discrimination, conformity and pluralistic ignorance, and the formation of impressions via personal perception(s) may influence adolescents while they are constructing their own body image. Erikson's stages of psychosocial development indicate that adolescence is a crucial period for the formation of self-identity, and how an adolescent sees himself is important to his own survival. Furthermore, ”body image” is one of the most important indicators by which we measure self-image. Here the author will discuss four key processes, namely, the process by which (1) adolescents are influenced by the mass media with regard to their physical and mental development; (2) adolescents are swayed by ”pluralistic ignorance”; (3) attitude problems are triggered by prejudice and discrimination; (4) stereotypes are clarified in relation to body image. The author hopes this paper can provide valuable counseling strategies for teachers, so that they can help adolescents to accept and appreciate themselves, and to be very positive about their futures.