The social networking website has been one of the most popular Internet websites in recent years. Lately social games such as "happy farm" drew a lot of attentions and accumulated millions of players in short period of time. The popularity of social games is changing the ecosystem of online games. Companies in this industry have to be concerned about the impact of it to keep their competitiveness. Technology acceptance model (TAM) has been pervasively used by researchers in that this model systematically helps the users to find out the process of user behaviors, and explores the impact of external variables which change the attitude and desire of users to adopt new technologies. This study reviewed the behaviors of social game players and used "perceived enjoyment", "perceived attractiveness", "social norms", and "platform service and corporate image" as the external variables and "intention toward playing social games", "customer preference", "customer loyalty" as the dependent variables in the TAM for social games. DEMATEL is used as the analysis tool in this study. The result shows that "social norms" and "perceived enjoyment" are the top two factors that can help to improve the popularity of social games. This study provides a reference to the companies in social game business and helps them to offer a more popular social game to players.