Turnitin is the world's leading paper detection system developed by American iParadigms company, which includes more than/kloc-0.50 billion paper databases, more than 90,000 world-renowned journals and magazines databases, and more than 20 billion web databases. It can be used to detect dissertations, classroom assignments, SCI and EI submissions. The utilization rate of universities in Britain and America is as high as over 90%, and some universities in China are also using it. Generally, the results of turnitin duplicate checking are basically safe below 15%, and each school generally has its own standards and requirements. Some schools may have higher requirements, while others may have lower requirements. Only when the duplicate checking rate of English papers is not higher than 20% can they be qualified.