Abstract: When revised, TP Category o f Classification in the Chinese Library ( 4th Edition ) appl ies the revision of the classification and technology in the old edition. Compared with the 3rd edition, the 4th edition in theTP category has the following features: supplementing many new categories and new category annotations; adjusting category system; revising or standardizing the category; supplementing the history annotations; etc. , which will help to make the book more scientific and more practical .

Key words: Classification in the Chinese Library ( 4th Edition), TP category, revision features