The purposes of this study are to find factors that have influences on the knowledge contribution activities, and to offer some suggestions to improve the knowledge contribution. Especially this study suggests to improve knowledge contribution by analyzing both on-line and off-line knowledge contribution activities in the public sector. The results of data analysis by structured equation model(SEM) indicate that leadership, intrinsic motivation, and knowledge quality significantly influence on-line and off-line knowledge contribution. Based on the results, the potential implications for the strategy of effective knowledge contribution are discussed.