The seal of a library is a kind of book seal, which is used to show the ownership of a book and confirm that the book belongs to the library collection. Usually, the chapter of the library will be covered on the front of the book, including the title page, the side and the inside page of the book. The purpose of this is to facilitate readers and staff to quickly identify books in the library and ensure that the ownership of books is clearly visible. The chapter of the library not only shows the ownership, but also has the function of theft prevention. When the book is stamped with the seal of the library, it can effectively reduce theft, because it is difficult for thieves to resell or hide books with the library logo. Such signs also remind readers and borrowers to cherish the books in the library, abide by the borrowing rules and maintain the order and resources of the library.