Patent document refers to a document written in accordance with the format and content requirements stipulated in the patent laws of all countries in the world, which specifically records the specific technical scheme for applying for a patent. Theoretical discovery is not the object of patent law protection, so it will not be recorded in patent literature. The characteristics of patent literature are as follows: ① a large number and a wide range of contents; (2) Integrating technical, legal and economic information; ③ Disseminating the latest scientific and technological information; ④ Uniform format and standardized form.