This study was designed to examine the policy role of the provincial governments' think tanks. Various subjects of research reports that 15 provincial governments' think tank across Korea have published for the last two decades were reviewed and categorized into six areas such as administrative management, economic area, non-economic area, regional SOC, administrative support, and emergency management in order to accomplish the goal of this study. The frequencies of six research areas were analyzed both in a 20 year longitudinal view and a cross-sectional view across 15 individual think tanks. This study showed that these think tanks contributed to produce prescriptive knowledge to resolve local problems by publishing over 10 thousands research reports in 37 subdivided research areas. This also study showed that the subjects of research reports, that these think tanks have published, met the needs of provincial governments, reflected the situation and change of regional political and economic surroundings. For instance, the think tanks supported by more urbanized provincial governments such Seoul, Busan, Inchon, etc. emphasized non-economic areas such environment and welfare, while those supported by less developed provincial governments such as Chungnam, Chungbok, Kyungnam stressed economic areas such as tourism and industrial policies. Further action is required for these think tanks to help themselves tanks establish “prescriptive" knowledge network between public and private think tanks, regional and national think tanks, policy research and policy advocacy think tanks, and across regional think tanks.