「虛擬社群」提供了網路使用者一個彼此互動和分享資訊與知識的環境，近年來線上遊戲盛行，和線上遊戲相關的「社群」紛紛成立，以留言形式的「遊戲論壇」成為重要的遊戲經驗、知識及技能交流平台。在論壇中分享、提供知識是一件勞心勞力，甚至是有害無益的事情，因為會造成在遊戲世界中被超越的危機。就論壇經營者的角度而言，愈多人分享，會吸引愈多會員，也會有更多的收益。因此，遊戲論壇中的知識分享者的分享願意是一個相當值得研究之主題。本研究以「理性行動理論」為基礎，結合「利他主義」、「社會交換理論」以及「沈浸理論」來探討論壇成員的知識分享行為，本文加入「利他主義」、「聲譽」、「沉浸狀態」為影響成員知識分享態度的因素。本文以各大遊戲論壇成員為樣本，發放網路問卷，共回收有效問卷 755 份，研究結果顯示聲譽、利他主義及沉浸狀態對知識分享態度有正向顯著的影響，而知識分享態度及主觀規範對知識分享意圖亦為正向影響，對遊戲論壇的使用者而言，知識分享意圖會進一步導致知識分享行為。所以論壇管理者可以在網站內部提昇網站的黏著度並增加優質發言者的聲譽，在外則須提昇遊戲論壇的正面評價以增加論壇會員人數。

The Internet is now the most frequently used tool. On the virtual gaming community website, community members from different regions can share their knowledge on a public platform. Sharing and providing game-related experience and information might not only be laborious, but also cause the risk of being surpassed in the virtual world of the game. However, the more people share will attract more members, and then the revenue increased. Therefore, the study about why forum members are willing to share knowledge on a platform has become a worth researching topic. The purpose of this research was to test a hypothesized model regarding Theory of Reasoned Action (TRA), Social Exchange Theory, Altruism, and Flow Theory to analyze the motivations of the sharing behavior on on-line game forums. A web-based questionnaire was designed, valid questionnaires were 755. Empirical results reveal that reputation, altruism and flow states have positive effects on attitude of knowledge sharing. The attitudes of knowledge sharing and subject norms also have positive effects on intention of knowledge sharing. Therefore, administrators of on-line game forums site have to increase the reputation of high-quality posters and to enhance the positive assessment of on-line game.