Since the appearance of the library, it has been the main place for human beings to accumulate and spread knowledge. Libraries enable human beings to enjoy knowledge, and the popularity of libraries makes the pursuit of knowledge no longer the patent of a few privileged classes. The public can also borrow books and documents through the library to increase their knowledge and broaden their horizons. It can be said that the development of library cause is an important symbol of human social civilization.

With the advent of the information age, the status of the library has become more and more important, but at the same time, under the new socio-economic and technological environment and the great wave of knowledge economy, the library is also facing new challenges.

In traditional libraries, the dissemination of information recorded in books depends entirely on its material carrier: one book at a time, the knowledge in one book cannot be enjoyed by multiple readers at the same time, and readers must borrow it in person and need to queue up. And they will encounter the trouble that "this book has been lent out". Library retrieval tools are not perfect, and sometimes finding a book is like looking for a needle in a haystack, which is time-consuming and laborious. What a pleasant thing it would be if you could directly read and download the books, articles or data you need on your computer through network transmission! Today, all this is no longer a dream. Making full use of modern information technology to solve the disadvantages of the existing library mechanism, digital library came into being.

Digital library is a library built on the Internet, also known as "virtual library".