This study aims to explore the Pedagogical Content Knowledge(PCK) for cooperative learning and propose a direction for the design of online cooperative learning that reflects it. In order to achieve this, Focus Group Interview(FGI) were conducted with five experts to gather the practical knowledge of instructors that leads to learner participation and interaction. The PCK for cooperative learning was revealed through the Delphi method centered on the theory of cooperative learning. Subsequently, computer technology capable of effectively supporting these knowledge was discussed, considering the educational situations in which the knowledge is applied. As a result of the research, over 50 PCK related to the basic principles of cooperative learning and the educational practice of cognitive factors of cooperative learning were concretized. A direction for the design of an online cooperative learning program to support this effectively was proposed. The results of this study contribute to the innovation and development of university liberal arts education by concretizing the capabilities and knowledge necessary for instructors in cooperative learning. It also provides useful knowledge for designing computer-based educational platforms or programs for non-face-to-face online cooperative learning.