The libraries have been the core (or heart) of the schools and the primary sources of acquiring knowledge and circulating information for all teachers and students. The progress of technology not only has impacts on the development of modern civilization but also involves in the protection of intellectual property, however.This article tries to set a boundary on the behaviors of copy in libraries by clarifying the definition of libraries, copying, and duplication and by study of empirical cases in real world. With that, we hope to reduce the arguments between teachers/students and the librarians in campus arising from behaviors of copy and to build up the concept of respecting and protecting Law of Copy Right accordingly.