The Library of Congress was originally built in the Capitol. 18 14, the British army burned down the parliament building and all the books were destroyed. 18 15, President Jefferson sold his 6,487 books to the Library of Congress, which laid the foundation for the collection of books in the library.

Starting from 1870, according to the copyright law, all books published in the United States must be submitted to the Library of Congress in two volumes. 1897 moved into Jefferson building. 1899, classified compilation of the Library of Congress. Starting from 190 1, printed catalogue cards will be distributed to libraries at home and abroad. 1909 ~ 19 14 published the dictionary catalogue of the library of congress. 65438-0927 published the national joint catalogue, which contains all the book catalogues of more than 10 large libraries in the United States and Canada 1 100. Adams building was built in 1939. 1969, MARC-II tape was officially released to libraries and information systems. 197 1 year started cataloging in edition to provide cataloging materials for publishing houses. 1983 Madison building opens. Since 1960s, libraries have been engaged in standardization and automation, and now they have realized computerization in purchasing, cataloging, circulation, reading, copying, retrieval and management. In addition, the National Library has also played a role in studying ways to preserve materials, carrying out book exchange and serving the disabled.