Knowledge payment based on social media has become a new business model. The research on adoption intention of users could help the users recognize the influence of knowledge payment. Meanwhile, the research is helpful for the suppliers to standard and develop this business model further. According to the social media nature of knowledge payment, use and gratification theory and technology acceptance model were chosen as the theory basis to build the research model of users' adoption intention on knowledge payment. 315 valid samples were collected from questionnaire. Structural equation model was used as the model analysis tool. It is found that the main motivations and purposes of users' adoption on knowledge payment are the willingness to get cognitive gratification, hedonic gratification, and convenience gratification of the users. Meanwhile, in order to increase the users' adoption intentions, knowledge content represented by perceived usefulness is critical, operation process represented by perceived ease of use is the method, but perceived payment price is not the key factor.