This study analyzes that Korea online-game emerges by naturally developed demanders, not by intentional suppliers(government/firms). Knowledge Ecological Approach is used to explain the emergence of Korea online-game industry. The research shows several knowledge factors that Korea online-game developed successfully. First, newly developed human resource(mainly lead users) play a strong positive feedback in the knowledge ecology system. The interactive system consists of social & environmental actors(local/global technological textbooks, universities, informal education institutes, companies etc.). Second, early developers start up venture firms through on/offline creative communities which give them project based job experience. Policy implication of the research is that the naturally emerged knowledge ecology, where various actors interact efficiently, determines the fountain new industry rather than discontinuous, intentional physical resources.