Abstract：Connected to both copyrights and its limitation, any changes of fair use doctrine will somehow rebuild copy-right law. Even impacted by new technology, rights allocation by copyright market should not be interrupted at will，and fair use should abide by its original justification, which is to remedy the market failure in copyright market. When the use of copyrighted works is for public purpose, market failure based on transaction costs or positive externalities needs to be considered, and the effect of the use upon the potential market for the copyright-ed work should be treated as the key factor. These rules can keep the copyright as private right and be the best way to define the Scope of fair use.
2011, Vol. 0 
