Orphan drug refers specifically to those treating rare diseases，while due to relatively small amount of sick people，small market size，higher research and development cost and so forth，pharmaceutical enterprises generally are unwilling to develop such drugs. Under the “market failure”，the government needs to develop drug regulatory policies so as to promote the development of orphan drug R&D，accelerate orphan drug marketing process and thus ensuring orphan drug accessibility. Based on comparative legal analysis of several orphan drug special marketing authorization system including designation，special registering and approving system，reexamination regime，compassion use in the United States，European Union，Japan，Taiwan and other countries or regions outside，thereby providing recommendations for improving Orphan Drug Special Marketing Authorization System in China.