Based upon Keaveney's Customer Switching Model, this study explores the customer switching behavior of flow players in online game. In this study, the researchers reconsider several key factors influencing massively multiplayer online game players, including satisfaction, regret, and switching barriers. The study attempts to find out the facts of the flow player participation motivation and behavior, flow player characteristics and experience, and the motivation of flow player switching behavior. An internet questionnaire was posted and asked for answers. 7,558 were examined as effective samples, in which 2,203 subjects were identified as flow players. The findings of this study include: (1) Game design, online services provided by the game master, network connection quality, and real-word customer services are keys issues for game satisfaction; (2) Update speed of the competing product and their game design are two critical factors for the player's regret; (3) the costs resulted from the switching are the important factors for switching barriers. These results could be transferred into e-Learning material design, information services, and website operation, in order to encourage the learner's continual learning process.