On the Basis of comparison among electronic library,digital library and virtual library,this article put forward a viewpoint:in 21 century,the main body of library is digital library.

• 本文在比较电子图书馆、数字图书馆和虚拟图书馆三种新形态图书馆基础上,提出21世纪图书馆的主体形态是数字图书馆。