Copyright law and library have drawn much attention of researchers in library science and law all over the world in recent years. The formation of the networked environment has led to the change of the copyright law. Thus we are confronted with many questions and problems that have to be answered and solved in the development and management of the digital libraries. Advancing and solving these questions and problems are new subject of the library science research. This dissertation uses various methods, including document investigation and analysis, internet resource investigation and analysis, practice investigation, quantitative analysis, case study, compare investigation, synthesis, induce, etc., to study the problems related to Copyright law and library from theory and practice.Copyright law in modern sense has lasted about three hundred years. The dissertation give a concise and systematic discussion on following aspects, such as the origin and development of copyright law, the basis of copyright legislation, the aim and principle of copyright legislation, the function of copyright law, the evolution and basis of the fair use institution. This serves as a foundation for further study.The communication and use of digital works differ from traditional ones. This dissertation illustrates the formation of the networked environment and its influenceon copyright laW analyzes the cause of copyright problem, proves the necessity ofthe protection of the new digital works and its comrnunication through the network,also proves the rationalization to expand the fair use to networked environment andto restrict the new established rights.Through the study on WIPO Copyright Treaty, The Digital MillenniumCopyright Act of U.S.A., and The Revision Draft of The Copyright Law of ThePeople's Republic of China, the author find that the new copyright laws lay unduestress on protection of the copyright owner's rights, but neglect to restrict the newrights. Thus the balance of the copyright is broken, users caxmot use the copyrightedworks conveniently as in print environment, and libraries cannot carry on resourcearchiving and delivery according to fair use exceptions as usual. The dissertationthoroughly reviews and compares fore mentioned copyright laws, puts out somepractical suggestions on revision of copyright law of our country, and fills the gapsin this research field.The dissertation analyzes the influence of the changing copyright laws onmanagement and service of libraries, introduces the various effOrts made byinternational library conununity to prevent the hannful impact.Copyright should be considered when establishing the construction model ofthe digital libraries. The dissertation analyzes the legal environment of the digitallibraries, expounds the importance to avoid infringement, compares the differentmeasures to settle the copyright problems, makes suggestions on principle andpolicy to solve many problems., and finally, points out the urgent tasks in front oflibrary community of our country. (l chart, 5 tab1es, and 384 references)