Abstract: The internet has been penetrating into almost every part of our life, affecting the society and everybody, comprehensively and greatly, especially for adolescents, who are at the critical stage of their lives. Based on Bronfenbrenner’s ecological theory of human development, from four facets, including microsystem, mesosystem, macrosystem, and adolescents themselves who locate the center of the ecological system, this article dissertated thoroughly the close relationships between internet use and adolescents’ self-identity. Then some primary knowledge about internet use’s influence on adolescents’ physical and mental development was provided

Key words: internet use, interpersonal relationship, peer relationship, self-identity