Online knowledge payment system is a new product of knowledge management and knowledge sharing in the digital economy era. Starting from the development course and trend of digital payment system, this paper firstly analyzes the technological changes and dimensions of digital payment system, and then analyzes the theory, operation mode, technological changes and risks of the digital payment system of online knowledge payment system. The digital payment system of online knowledge payment system mainly analyzes three types: wholesale type, retail type and cross-border type; wholesale type mainly improves its security and predictability; retail type mainly improves the quality of user experience and reduces the cost-effectiveness of users; cross-border type mainly improves its real-time performance; Transparency, predictability and traceability are the main factors.