Nowadays，paying for knowledge has become a new trend of the internet industry.Its rapid development mainly results from the internet users' increasing demand caused by their knowledge anxiety in information explosion age；the popularization of online payment and users' adaptive behavior of paying for content also contributes to it.With more than one year explosive growth，pay-for-knowledge industry has covered more and more users and formed several fixed types including Paid Answer，Paid Column，Paid Community，Paid Course and Contribution.Based on analysis of the present condition，this paper will further explore pay-for-knowledge trend and its influence on other fields like publication，education and E-commerce.