"China Library Classification Number" refers to the classification code obtained by analyzing the subject of scientific and technological documents with "China Library Classification" and organizing the documents in different categories according to the subject attributes and characteristics of the documents.

The Classification Number of China Library adopts a mixed number of English letters and Arabic numerals, with one letter representing a major category, reflecting the alphabetical order of major categories, and the letters are marked with numbers.

Functions and characteristics

China Library Classification Number is a unified book number compiled for the convenience of retrieval, which is used by information units and book archives departments to classify books, organize collections and compile document retrieval catalogues. Each paper should be indexed according to the classification number of China Library Classification (4th Edition). For papers involving multiple topics, a paper can give multiple classification numbers, with the main classification number at 1 and multiple classification numbers separated by semicolons.