This study focuses on how public libraries in East Germany adjusted themselves into new environments after the unification during 15 years(1990~2005). First, system and operation of East Germany's public libraries are studied and public libraries in West and East Germany are compared before the unification. After public libraries in East Germany became unified with West Germany, the structure of East Germany's public libraries changed, many of public libraries and labor libraries were closed and collection in those libraries was discarded or replaced. Thus, it is studied how libraries enhanced their capabilities and discovered their roles or identities in changing situations in this research.