In the context of the global economic turmoil, the online gaming industry shows a steady and rapid growth. There are many supporters of online games in China; the data of China Internet Network Information Center (CNNIC) shows that: by the end of 2012, the size of domestic online game users had reached 336 million. Although the rich profit, the online gaming industry faces fierce competition, so it’s particularly important to establish and maintain customer loyalty. The loyalty to online games comes from brand loyalty, and it’s defined that: the gamer has a strong preference for the games involved, even faced with some situational changes; it would not affect the gamers’ willingness and behavior to continuing playing games. So far, only few studies have investigated the factors influencing the loyalty to online games. Previous studies had shown that the human-computer interaction, social interaction, gamers’ interaction behavior, social norms, the cohesion perceived, trust, switching costs, the fun sense of euphoria perceived and customization would affect online game loyalty. In addition to this, customization is also an important factor influencing the loyalty to online games. Customization refers to the degree that one can create, select and change techniques, goods and services based on personal preferences. The studies about customization have covered many areas, including the food industry, electronics industry, large-scale engineering manufacturing industry and Mobile Phone industry. Although the positive correlation between the loyalty to online games and customization has been confirmed by few studies, the mechanism of customization’ impact on the loyalty to online games is not clear. The purpose of this study is to investigate the customization’ impact on the loyalty to online games and test the mediation role of character attachment between them. The present study used questionnaire research methodes to investigate the impact of customization in online games and character attachment on the loyalty to online games, and the participants were 459 male college students. Three questionnaires were used in this study: Online Game Customization Questionnaires includes four items using a 7-point Likert scoring; Game Character Attachment includes eighteen items using a 7-point Likert scoring; the Loyalty to Online Games Questionnaires includes five items using a 5-point Likert scoring. The results showed that: (1) Among these three variables, there existed positive correlation between each two variables; (2) Customization in online games had no direct impact on the loyalty to online games, but it could impact the loyalty to online games through the full mediation of character attachment. The results of this study suggest that, much attention should be paid to customization, especially to the customization of game character in the design process of online games. Diversification and differentiation is the basis for customization. Currently, there are few female online gamers, this is because that game character design and customization may simply reflect the preferences of male gamers and are unable to meet the psychological needs of female online gamers. So in the future, the online game developers should design as many different game characters as possible, and provide different featured game services. They should especially pay attention to female gamers’ features, design characters matching female gamers’ need, and meet females’ pursuit of unique of psychological through customization.