1. Electronic document delivery: With the development of network technology, more and more libraries begin to provide electronic document delivery services. Users can download the required electronic files through the library website.

2. Inter-loan of document collection institutions: through the inter-library loan agreement, the collections of other libraries are provided to users in need by means of mutual loan, taking advantage of the collection advantages of each library.

3. Document delivery is an irreversible document providing service. Users can obtain the required copies of documents through institutions such as libraries or document delivery centers. This service is fast, efficient and simple, and can meet the needs of users for the lack of periodical papers, books and other documents in the library. The ways of document delivery include copy delivery, microfilm delivery, electronic document delivery, mirror service and document collection agency lending. Modern document delivery is developed from interlibrary loan with the support of information technology, but it is a better service than interlibrary loan. By carrying out document delivery service, the contradiction between the shortage of library funds and resources and the increasing demand of readers for documents is not only alleviated, but also plays a very good supporting role in teaching and scientific research.