This study examined the characteristics of two keyword types expressing the topics in the intellectual structure analysis based on the co-word analysis, focused on overseas open access field. Specifically, the keyword set extracted from the LISTA database in the field of library and information science was divided into two types (controlled keywords and uncontrolled keywords), and the results of performing intellectual structure analysis based on co-word analysis were compared. As a result, the two keyword types showed significant differences by keyword sets, research maps and influences, and periods. Therefore, in intellectual structure analysis based on co-word analysis, the characteristics of each keyword type should be considered according to the purpose of the study. In other words, it would be more appropriate to use controlled keywords for the purpose of examining the overall research trend in a specific field from the perspective of the entire academic field, and to use uncontrolled keywords for the purpose of identifying detailed trends by research area from the perspective of the specific field. In addition, for a comprehensive intellectual structure analysis that reflects both viewpoints, it can be said that it is most desirable to compare and analyze the results of using controlled keywords and uncontrolled keywords individually.