OBJECTIVES: This research analyzed knowledge structure and its effect factor by evaluation of coauthor and keyword network in Korea's Epidemiology sector. METHODS: The data was extracted from 318 papers listed in the Korean Journal of Epidemiology, and was transformed into 643 coauthors and 131 keywords matrix. In this matrix a link was judged by impact factors which were calculated by the weight value of what the role was and the rate of how many authors participated. We verified that the research achievement was dependent upon the author's status and network index. RESULTS: The results showed a small world effect according to the development of a random network in the center of a few high productivity researchers. In particular, degree centrality was more developed than closeness centrality. Also, power law distribution was discovered in impact factor and research productivity by college affiliation. In multiple regression, the effect of the author status was significant in both the impact factor calculated by the participatory rate and the number of listed articles. Moreover, a small group of researchers with outstanding research productivity carried out many of the core academic activities in the Journal of Preventive Medicine and Public Health. CONCLUSIONS: This study shows that the small world phenomenon exists in coauthor and keyword networks in the unit of journal like as citation networks. However, the coauthor networks in the field of epidemiology was more differentiated than the preventive medicine field.