This paper describes the generation,concepts,basic features,and the models of a digital library.The authors,especially,present that a dream of the electronic library is able to come true under Internet environment,and a real electronic library model consists of four structure levels which are user interfaces,networks and communications,information resource,and reference service system. There are five functions in the digital library which are digitized documents for various media,storage,access,transmission, privilege and management.The authors are planning to create an embryonic form of a digital library in Shanghai Jiantong University.