Abstract: The rapid development of information network technology and the outbreak of pandemic have prompted the traditional teaching to gradually develop into a new form of online and offline mixed teaching. Based on activity theory and DIKW information chain, this study explores the construction of online and offline mixed teaching mechanism. According to the activity theory, the analyses of the relevant teaching mechanism structure elements are as follows: subject, object, community, tools, rules, and division of labor. Combined with the DIKW information chain, this paper discusses the knowledge construction process in the four subsystems of production, communication, consumption and distribution in the teaching mechanism system, so as to build a new online and offline mixed teaching mechanism.