Graduation in June is just around the corner, and some colleges and universities have already started the arrangement of thesis writing, and the thesis writing in about one month is compact. A month is not enough to write a good paper. We should collect information, synthesize information, analyze information, write papers, and check the similarity of the most important papers in the next step. In most colleges and universities in China, the graduation thesis has been basically completed and entered the final stage. In order to prevent their papers from being identified as plagiarism by the school to check the similarity, most students have collected a large number of papers on the Internet to check the similarity of their papers after repeated self-examination. Finally, enter the school papers to see the importance of similarity detection. It is a good opportunity for the business of companies that re-examine papers, and some unscrupulous businessmen turn students' re-examination papers into "money transactions", sell re-examination papers online like students, and then resell students' papers online to make profits. However, there are still many paper duplicate checking companies in China that provide safe and reliable paper duplicate checking system services, among which PaperRater paper duplicate checking system is the most representative.