Data trading is an important form of data elements circulation. By constructing an evolutionary game model of "data trading platform - data providers - data demanders," it is revealed that the data trading market exists in three equilibrium states: non-cooperation, inefficiency, and ideal. A higher initial willingness for technological innovation by the platform, a reasonable profit distribution coefficient, and a lower loss of competitive advantage can promote the system to evolve towards an ideal equilibrium state; whereas high data prices and technological innovation costs can lead the system into a state of non-cooperation or inefficiency. Therefore, the development of the data trading market can be promoted by enhancing the awareness of the subjects, establishing a fair and reasonable profit distribution mechanism and data product pricing, and supporting technological innovation in the platform.