Abstract: With the rise of knowledge payment economy,what role should libraries play with"knowledge center"and"Learning Center"as their mission?Although both the knowledge payment platform and the library are providing knowledge services,they are different in service motivation,knowledge production,target users and development direction.The library should play the four roles of knowledge guarantee,knowledge evaluation,knowledge inheritance and knowledge economy incubation under the environment of knowledge payment economy.

Key words: knowledge payment；knowledge service；library