Library takes its way to digitalization to fill its role in modern information society. This study discusses social environment of this trend and investigates library circumstances, and refines the meaning of a library. A digital library is led by current stream of new media, rapid development of digital technology and recording methods, and revolution of information circulation and production such as electronic publishing. However, rich information sources in printed forms are even significant as a ground of a digital library. The digital library is not a brand-new feature of a library but the result of digitalization of information resources to accomplish the purpose of the library.